Water-soluble film containing metal salts

Abstract

A water-soluble film comprising a mixture of polyvinyl alcohol (PVOH) resin, a plasticizer, and a metal salt, wherein the metal salt is present in the water-soluble film in an amount sufficient to reduce the enthalpy of melting of the film by at least 20% compared to the enthalpy of melting of a film otherwise identical without the metal salt.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 464,719, filed on 8 May 2023, and U.S. Provisional Patent Application No. 63 / 592,056, filed on 20 October 2023, the entire disclosures thereof being incorporated herein by reference.

[0002] This disclosure generally relates to water-soluble films and related articles. More specifically, this disclosure relates to water-soluble films containing one or more metal salts. [Background technology]

[0003] Water-soluble polymer films are commonly used as packaging materials to simplify the distribution, injection, dissolution, and dispensing of materials being delivered. For example, pouches made from water-soluble films are commonly used to package household care compositions such as laundry detergents and dish soaps. Consumers can add these pouched compositions directly to mixing containers such as buckets, sinks, or washing machines. Advantageously, this provides precise dispensing while eliminating the need for consumers to measure the composition. These pouched compositions can also reduce the hassle associated with dispensing similar compositions from containers, such as pouring them from bottles. In short, soluble, pre-measured polymer film pouches offer convenience of use for consumers in a variety of applications.

[0004] Pouches containing water-soluble films can be manufactured, for example, by thermoforming. Thermoforming of a film is a process in which the film is heated, shaped (for example, in a mold), and cooled so that the film retains its shape, for example, the shape of the mold. Reducing the temperature at which water-soluble films can be thermoformed can improve manufacturing costs and throughput, for example, by reducing energy requirements and heating and cooling times. However, such improvements should not be made at the expense of film properties related to the manufacture or use of the pouch, such as acceptable mechanical strength, flexibility, and solubility.

[0005] It has been reported that the properties of polymer films can be altered by adding one or more metal salts. In particular, several authors have noted that the addition of metal salts to polymer films can generally have a plasticizing effect, as evidenced by the decrease in the glass transition temperature (Tg) of the film as the metal salt content increases. For example, Jiang et al. (Carbohydrate Polymers, 90(2012)1677-1684; Intl. Journal of Biological Macromolecules, 82(2016)223-230) describe the plasticization of starch / polyvinyl alcohol films by adding various metal chloride salts. Some of the added salts had adverse effects on water adsorption or thermal stability.

[0006] Bhajantri et al. (Polymer, 47(2006)3591-3598) describe the effects of barium chloride doping on the optical, thermal, and structural properties of polyvinyl alcohol films. The authors concluded that the dopant acted as a plasticizer, but that high dopant concentrations led to phase separation into polymer-rich and dopant-rich phases.

[0007] Zidan (J. Appl. Polym. Sci., 88 (2003) 1115 - 1120) describes the thermal properties of PVOH films filled with chromium fluoride and manganese chloride. Generally, an increase in the filler content reduces the Tg and decomposition temperature of the film, and the authors concluded that the filler acted to plasticize the film.

[0008] There is a need in the art for a water - soluble film that can be thermoformed at low temperatures for packaging to hold liquid compositions, has good mechanical properties and solubility, and maintains good mechanical properties and solubility after thermoforming. SUMMARY OF THE INVENTION

[0009] One aspect of the present disclosure provides a water - soluble film comprising a mixture of a polyvinyl alcohol resin, a plasticizer, and a polyvalent metal salt containing an inorganic anion, wherein the polyvalent metal salt is present in the water - soluble film in an amount sufficient to reduce the melting enthalpy of the film by at least 20% compared to the melting enthalpy of an otherwise identical film that does not contain the polyvalent metal salt, and the polyvinyl alcohol resin is present in the film in an amount of at least 50% by weight based on the total weight of the film.

[0010] Another aspect of the present disclosure provides a water - soluble film comprising a mixture of a polyvinyl alcohol resin, a plasticizer, and a lithium salt.

[0011] Another aspect of the present disclosure provides a water - soluble film comprising a mixture of a polyvinyl alcohol resin, a plasticizer, and a salt, wherein the film has a resistance in the dry state of less than about 60 MΩ (megaohm), or less than about 50 MΩ, or less than about 40 MΩ, or less than about 30 MΩ. The salt can be selected from the group consisting of guanidinium chloride, potassium chloride, ammonium chloride, and potassium iodide.

[0012] Another aspect of the present disclosure provides a water - soluble article formed by thermoforming a water - soluble film according to the present disclosure.

[0013] Another aspect of the present disclosure provides a method for forming a water-soluble article, which includes thermoforming a water-soluble film according to the present disclosure.

[0014] Another aspect of the present disclosure provides a water-soluble fiber comprising a mixture of a polyvinyl alcohol resin, a plasticizer, and a polyvalent metal salt.

[0015] The compositions and methods described herein include, but are not limited to, constituent elements, their compositional ranges, substituents, conditions, and steps, and optional features may be selected from the various embodiments, examples, and examples provided herein.

[0016] Further embodiments and advantages will become apparent to those skilled in the art through consideration of the following detailed description in conjunction with the drawings. While films, articles, pouches, and methods for manufacturing and using them may take on various forms, this disclosure is illustrative and is not intended to limit the invention to any specific embodiments described herein. Specific embodiments are included below. [Brief explanation of the drawing]

[0017] To further facilitate the understanding of the present invention, three drawings are attached herein.

[0018] [Figure 1] The DSC trace of the water-soluble film of the present disclosure, as described in Example 1a, is shown. [Figure 2] The DSC trace of the water-soluble film of the present disclosure, as described in Example 1b, is shown. [Figure 3] The DSC trace of the water-soluble film of the present disclosure, as described in Example 1c, is shown. [Modes for carrying out the invention]

[0019] This disclosure provides a water-soluble film comprising a mixture of polyvinyl alcohol (PVOH) resin, a plasticizer, and a polyvalent metal salt containing an inorganic anion, wherein the polyvalent metal salt is present in the water-soluble film in an amount sufficient to reduce the enthalpy of melting of the film by at least 20% compared to the enthalpy of melting of an otherwise identical film that does not contain the polyvalent metal salt, and the PVOH resin is present in the film in an amount of at least 50% by weight, based on the total weight of the film.

[0020] This disclosure also provides a water-soluble film comprising a mixture of polyvinyl alcohol (PVOH) resin, a plasticizer, and a lithium salt.

[0021] The films of this disclosure offer, surprisingly, one or more advantages, including, but are not limited to, improved thermoformability at temperatures below typical thermoforming temperatures, reduced enthalpy of fusion, and / or reduced enthalpy of crystallization compared to otherwise identical films that do not contain metal salts.

[0022] "Comprising," as used herein, means various components, constituents, or steps that may be jointly used in the practice of this disclosure. Thus, the term "comprising" encompasses the more restrictive terms "consisting essentially of" and "consisting of." The compositions may include, be essentially of, or consist of any of the required and optional elements disclosed herein. The inventions disclosed exemplary herein may be preferably carried out in the absence of any element or step not specifically disclosed herein.

[0023] Films such as those produced in accordance with this disclosure are defined by the polymer industry (Encyclopedia of Polymer Science and Technology, John Wiley & Sons, Inc., 1967, Vol. 6, page 764) as "molded plastics that are relatively thin for their breadth and width, with a maximum thickness of 0.010 inches."

[0024] The films of this disclosure may be self-supporting films and / or uniform films. A self-supporting film is a film that can support its own weight. A uniform film means a film that is virtually free from breakage, tears, holes, bubbles, and stripes.

[0025] To be considered a water-soluble film according to this disclosure, the film must be about 1.5 mil (about 0.038 mm) thick and dissolve in water at 20°C (68°F) in 300 seconds or less, according to MonoSol Test Method MSTM 205. A film according to this disclosure can be considered water-soluble if a film about 1.5 mil (about 0.038 mm) thick dissolves in water at 20°C (68°F) in 250 seconds or less, 200 seconds or less, or 150 seconds or less, according to MonoSol Test Method MSTM 205.

[0026] Unless otherwise specified, all percentages, parts, and ratios are based on the total dry weight of the formed film composition, and all measurements are taken at approximately 25°C. All such weights related to the listed components are based on their activity levels and, therefore, do not include carriers or by-products that may be present in commercially available materials, unless otherwise specified.

[0027] All scopes described herein include all possible subsets of scopes and any combination of such subsets. By default, scopes include the endpoints described unless otherwise stated. Where a range of values ​​is provided, it is understood that the values ​​between each of the upper and lower limits of that scope, and any other described values ​​within or between that scope, are included in this disclosure. The upper and lower limits of these smaller scopes may independently be included within smaller scopes and are subject to any specifically excluded limits within the scopes described and included in this disclosure. Where a scope described includes one or both of these limit values, the scope excluding one or both of these included limit values ​​is also intended to be part of this disclosure.

[0028] The dimensions and values ​​disclosed herein should not be understood as strictly limited to the exact numerical values ​​listed. Instead, unless otherwise specified, each such dimension is intended to include both the listed value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "15 mm" is intended to include "approximately 15 mm." The term "approximately" is used according to its usual meaning, for example, to mean roughly or around it. The term "approximately" may mean ±10% of the stated value or range of values. The term "approximately" may mean ±5% of the stated value or range of values. The term "approximately" may mean ±2% of the stated value or range of values.

[0029] As used herein, and unless otherwise specified, the terms “wt%” and “wt%” are intended to refer to the composition of a specified element in parts by weight of “dry” (non-aqueous) parts of the entire film (if applicable) or in parts by weight of the entire composition enclosed in the pouch (if applicable). As used herein, and unless otherwise specified, the term “PHR” is intended to refer to parts of the composition of a specified element per 100 parts of the water-soluble polymer (or resin, polyvinyl alcohol, or whatever) in the water-soluble film.

[0030] The film can be produced by solution casting or by melt extrusion. The film can be used to form an article or pouch by thermoforming a film layer around the article and by any suitable process including, for example, solvent sealing or heat sealing. The pouch can be used, for example, for input materials to be delivered to bulk water.

[0031] Unless otherwise specified, the films, articles, and related manufacturing and usage methods are considered to include embodiments that include any combination of one or more of the elements, features, and steps further described below (including those shown in the examples and drawings).

[0032] Water-soluble film The films and related articles and pouches described herein may include water-soluble films containing metal salts, the metal salts being distributed throughout the film. The water-soluble films may be solution-cast. The films may optionally further include one or more additives selected from plasticizers, fillers, surfactants, antiblocking agents, antioxidants, defoamers, bleaching agents, aversive agents, irritants, other functional components, and combinations thereof. In one embodiment, the water-soluble film may include a PVOH resin containing one or more PVOH polymers in at least about 50% by weight of the total dry weight of the film (i.e., the weight of the non-aqueous components).

[0033] The film can have any suitable thickness, with typical and particularly considered film thicknesses of approximately 76 microns (μm) or 88 microns. Other values ​​and ranges to consider include the range of approximately 5 to approximately 200 μm, or the range of approximately 20 to approximately 100 μm, or approximately 60 to approximately 120 μm, or approximately 70 to approximately 100 μm, or approximately 40 to approximately 90 μm, or approximately 50 to approximately 80 μm, or approximately 60 to approximately 65 μm, or approximately 20 to approximately 60 μm, or approximately 20 to approximately 50 μm, or approximately 30 to approximately 40 μm, for example, values ​​of approximately 35 μm, approximately 36 μm, approximately 50 μm, approximately 65 μm, approximately 76 μm, approximately 88 μm, or approximately 90 μm.

[0034] PVOH resin The films described herein may contain one or more polyvinyl alcohol (PVOH) polymers and may also contain PVOH copolymer resins, so as to constitute the PVOH resin content of the film.

[0035] Polyvinyl alcohol is a synthetic resin generally prepared by the hydrolysis or saponification of polyvinyl acetate, commonly referred to as alcohol decomposition. Completely hydrolyzed PVOH, where substantially all acetate groups are converted to alcohol groups, is a strongly hydrogen-bonded, highly crystalline polymer that dissolves only in hot water above approximately 140°F (approximately 60°C). When a sufficient number of acetate groups remain after the hydrolysis of polyvinyl acetate, i.e., when the PVOH polymer is partially hydrolyzed, the polymer is less hydrogen-bonded, less crystalline, and generally soluble in cold water below approximately 50°F (approximately 10°C). Therefore, the partially hydrolyzed polymer is a vinyl alcohol-vinyl acetate copolymer, commonly referred to as a PVOH homopolymer, although it is a PVOH copolymer.

[0036] The PVOH resin may include a fully or partially hydrolyzed homopolymer comprising vinyl alcohol monomer units and, optionally, vinyl acetate monomer units. The PVOH resin may also include a partially or completely hydrolyzed PVOH copolymer comprising anionic monomer units (i.e., anionic modified copolymer), vinyl alcohol monomer units, and, optionally, vinyl acetate monomer units. Anionic monomer units include vinyl acetate, alkyl acrylate, maleic acid, monoalkyl maleate, dialkyl maleate, monomethyl maleate, dimethyl maleate, maleic anhydride, fumaric acid, monoalkyl fumarate, dialkyl fumarate, monomethyl fumarate, dimethyl fumarate, itaconic acid, monomethyl itaconate, dimethyl itaconate, itaconic anhydride, citraconic acid, monoalkyl citraconic acid, dialkyl citraconic acid, citraconic anhydride, mesaconic acid, monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid, monoalkyl glutaconate, dialkyl glutaconate, and gluta anhydride. The compounds may be one or more of the following: ammonium compounds, vinyl sulfonic acid, alkyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, alkali metal salts of the aforementioned (e.g., sodium, potassium, or other alkali metal salts), esters of the aforementioned (e.g., methyl, ethyl, or other C1-C4 or C6 alkyl esters), and combinations of the aforementioned (e.g., multiple types of anionic monomers, or equivalent forms of the same anionic monomer). For example, anionic monomers may include one or more of monomethyl maleate and its alkali metal salts (e.g., sodium salt).

[0037] The water-soluble film may contain a single PVOH resin or a blend of two or more PVOH resins. For example, the film may contain a PVOH homopolymer, a PVOH copolymer, a blend of a PVOH homopolymer and a PVOH copolymer, a blend of two PVOH homopolymers, a blend of two PVOH copolymers, or a combination thereof. The water-soluble film of this disclosure may contain a polyvinyl alcohol homopolymer and may not contain anionically modified polyvinyl alcohol. The total amount of PVOH resin in the film may be in the range of about 50% to about 95% by weight, or about 60% to 90%, or about 65% to about 85%, based on the total dry weight of the film (i.e., the weight of the non-aqueous component).

[0038] The total PVOH resin content of the film may have a degree of hydrolysis (DH or DH) of at least about 68%, 75%, 80%, 84%, or 85%, and at most about 99.7%, 98%, or 96%, for example, in the range of about 75% to about 96%, or about 84% to about 90%, or about 85% to about 88%, or about 86.5%, or in the range of about 88% to 95%, about 89% to 93%, or about 89.5% to 92%, for example, about 89%, about 90%, about 92%, about 93%, about 94%, about 95%, or about 96%. As used herein, the degree of hydrolysis is expressed as the molar percentage of vinyl acetate units converted to vinyl alcohol units.

[0039] The degree of hydrolysis of a resin blend is also known as the arithmetic-weighted mean degree of hydrolysis.

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[0040] The viscosity (μ) of PVOH polymers is determined by measuring a freshly prepared solution using a Brookfield LV type viscometer with a UL adapter, as described in the Brookfield test method of the British standard ENISO 15023-2:2006 Annex E. It is international practice to state the viscosity of a 4% (w / v) aqueous solution of polyvinyl alcohol at 20°C. Unless otherwise specified, all viscosities specified herein in centipoise (cP) should be understood to refer to the viscosity of a 4% (w / v) aqueous solution of polyvinyl alcohol at 20°C. Similarly, where a resin is described as having (or not having) a particular viscosity, unless otherwise specified, the specified viscosity is intended to be the average viscosity of the resin having the corresponding molecular weight distribution.

[0041] Suitable PVOH resins for use individually or in combination are approximately 3 cP to 40 cP, or approximately 5 cP to 38 cP, or approximately 10 cP to 36 cP, or approximately 10 cP to 20 cP, or approximately 12 cP to 20 cP, or approximately 14 cP to 19 cP, or approximately 3 cP to 30 cP, or approximately 5 cP to 25 cP, or approximately 5 cP to 15 cP, or approximately 5 cP to 10 cP. Alternatively, it can have a viscosity in the range of approximately 5 cP to 7 cP, or approximately 12 cP to 34 cP, or approximately 14 cP to 32 cP, or approximately 18 cP to 30 cP, or approximately 20 cP to 28 cP, or approximately 21 cP to 26 cP, for example, 32 cP, or 26 cP, or 23.5 cP, or 21 cP, or 19 cP, or 16.5 cP, or 14 cP, or 6 cP. The viscosity of the PVOH resin is determined by the weight-average molecular weight of the PVOH resin.

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[0042] Other water-soluble polymers for use in addition to the PVOH copolymer in the film include, but are not limited to, polyacrylates, water-soluble acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, pullulan, water-soluble natural polymers (guar gum, gum acacia, xanthan gum, carrageenan, pectin, amylopectin, alginic acid and its salts, and starch), water-soluble polymer derivatives (modified starch, ethoxylated starch, and hydroxypropylated starch, but are not limited to these), copolymers of the aforementioned, and any combination of the aforementioned. Further examples of water-soluble polymers include polyalkylene oxides, polyacrylamides, polyacrylic acid and its salts, cellulose, cellulose ethers, cellulose esters, celluloseamides, polyvinyl acetates, polycarboxylic acids and their salts, polyamino acids, polyamides, gelatin, methylcellulose, carboxymethylcellulose and its salts, dextrin, ethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, maltodextrin, polymethacrylates, and any combination of the aforementioned. The film may contain polyethyleneimine, polyvinylpyrrolidone, polyalkylene oxides, polyacrylamides, cellulose ethers, cellulose esters, celluloseamides, polyvinyl acetates, polyamides, gelatin, methylcellulose, carboxymethylcellulose, carboxymethylcellulose salts, dextrin, ethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, maltodextrin, starch, modified starch, guar gum, gum arabic, xanthan gum, carrageenan, polyacrylates, polyacrylate salts, and copolymers of any of the aforementioned. Such water-soluble polymers, whether PVOH or otherwise, are commercially available from various sources.

[0043] metal salts In general, the water-soluble films of this disclosure contain metal salts. The metal salts may contain cations selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, manganese, barium, iron, aluminum, and mixtures thereof. The metal salts may contain cations having an ionic radius of 115 pm or less. While not intended to be theoretically bound, it is believed that the cations of the metal salts can partially crosslink the PVOH containing the water-soluble film, for example, through ionic crosslinking, disruption of polymer chain alignment, and inhibition or prevention of crystallization. It is also believed that as the ionic radius of the cation increases, the charge density of the cation decreases, reducing the strength of the crosslinking between the cation and PVOH, and thus reducing the effect of inhibiting or preventing crystallization. The metal salts may contain polyvalent cations. The polyvalent salts may contain divalent metal cations. The polyvalent metal salts may contain trivalent metal cations. The polyvalent salts may be selected from calcium salts, magnesium salts, manganese salts, barium salts, iron salts, and mixtures thereof. The polyvalent salts may be selected from calcium salts, magnesium salts, manganese salts, and mixtures thereof. Polyvalent salts can contain calcium salts. Polyvalent salts can contain magnesium salts. Polyvalent salts can contain manganese salts.

[0044] In some embodiments, the polyvalent metal salts do not contain zinc salts. Water-soluble films may not contain zinc salts. As used herein, and unless otherwise specified, “zinc salt-free” refers to a film having less than 0.5% zinc based on the total weight of the film. While not intended to be theoretically bound, the addition of zinc salts to polyvinyl alcohol-based films is generally considered to have less effect on the thermal properties of the film compared to the addition of other polyvalent metal salts, including but not limited to calcium, magnesium, and manganese salts.

[0045] Generally, polyvalent metal salts can contain inorganic anions. Inorganic anions can be selected from halides, nitrates, sulfates, phosphates, and combinations thereof. Inorganic anions can be halides. Halides can be selected from chlorides, fluorides, bromides, iodides, or combinations thereof. Inorganic anions can be selected from chlorides and fluorides. Metal salts can contain calcium chloride.

[0046] As shown in the following examples, metal salts do not have a direct plasticizing effect on the film. However, without intending to be bound by theory, when the film of this disclosure is exposed to moisture, such as under high humidity conditions, the presence of a salt having an inorganic anion can increase the film's ability to absorb water and effectively plasticize the film.

[0047] Water-soluble films may contain polyvalent salts containing inorganic anions and polyvalent metal salts containing organic anions. Suitable organic anions include, but are not limited to, acetates, citrates, glucons, lactates, and mixtures thereof. While not intended to be theoretically bound, salts containing organic anions are generally considered to be less effective at retaining water compared to salts containing inorganic anions, and therefore to provide less plasticization of the film through water uptake; however, polyvalent metal salts containing organic anions may be an additional source of polyvalent cations and are therefore considered to contribute to the reduction of crystallinity imparted by polyvalent metal salts containing inorganic anions.

[0048] In general, the amount of polyvalent metal salt in a film can be any amount sufficient to improve one or more film properties compared to a film that is otherwise identical and does not contain polyvalent metal salts. Such film properties may include, but are not limited to, enthalpy of melting, enthalpy of crystallization, glass transition temperature, Young's modulus, decay time, and dissolution time. Therefore, a polyvalent metal salt can be provided in an amount sufficient to reduce the enthalpy of melting of the film by at least 20% compared to the enthalpy of melting of a film that is otherwise identical and does not contain polyvalent metal salts. A polyvalent metal salt can be provided in an amount sufficient to reduce the enthalpy of melting of the film by at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 75%, or up to about 80%, or up to about 90%, or up to about 100%, compared to the enthalpy of melting of a film that is otherwise identical and does not contain polyvalent metal salts. While not intended to be theoretically bound, it is believed that a decrease in the enthalpy of melting of a given film reduces the temperature at which the film can be thermoformed. The films of this disclosure may have an enthalpy of melting of less than about 20 J / g, or less than about 15 J / g, or less than about 10 J / g, or less than about 5 J / g, or less than about 1 J / g, or less than about 0.2 J / g. Alternatively, the films of this disclosure may not exhibit a melting transition as measured by DSC and may have no enthalpy of melting.

[0049] A polyvalent metal salt can be provided in an amount sufficient to reduce the crystallization enthalpy of a film by at least 20% compared to the crystallization temperature of an otherwise identical film without the polyvalent metal salt. For example, a polyvalent metal salt can be provided in an amount sufficient to reduce the crystallization enthalpy of a film by at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 75%, or up to about 80%, or up to about 90%, or up to about 100%, compared to the crystallization enthalpy of an otherwise identical film without the metal salt. While not intended to be bound by theory, it is believed that a reduction in crystallization enthalpy allows the film to be thermoformed at lower temperatures. The films of this disclosure may have a crystallization enthalpy of less than approximately 50 J / g, or less than approximately 30 J / g, or less than approximately 15 J / g, or less than approximately 10 J / g, or less than approximately 5 J / g, or less than approximately 1 J / g, or less than approximately 0.2 J / g. Alternatively, the films of this disclosure may not exhibit a crystallization transition as measured by DSC and may have no crystallization enthalpy.

[0050] Generally, the glass transition temperature is the temperature at which a material transitions between a glassy state and a rubbery state. The films of this disclosure may exhibit a first glass transition temperature (Tg, or simply the glass transition temperature) and a second glass transition temperature (Tg2, or the dry glass transition temperature). Measuring the Tg of a film according to the DSC method described herein involves first cooling a sample of the film to -80°C and then heating the film sample to 200°C, with the glass transition occurring between these two steps. The films of this disclosure may contain water, and the presence of metal salts in the film can increase the film's ability to absorb water. The cooling step of the DSC method does not remove the water contained in the film sample; therefore, water is present in the film sample during Tg measurement, and Tg is the glass transition temperature of the film in its hydrated state (i.e., still containing water). However, heating the film sample to 200°C as part of the Tg measurement removes substantially all of the water contained in the film sample. Therefore, repeating the cooling and heating process on a film sample whose Tg has already been measured, as described in the DSC method, provides the glass transition temperature of a dry (i.e., substantially water-free) film composition. This second glass transition temperature measured on a substantially water-free film sample is denoted herein as Tg2.

[0051] The polyvalent metal salt can be provided in an amount sufficient to increase the glass transition temperature (i.e., the first glass transition temperature, or Tg) of the film by at least 10°C compared to the glass transition temperature of an otherwise identical film that does not contain the polyvalent metal salt. For example, the films of this disclosure may have a glass transition temperature at least about 10°C higher, at least about 15°C higher, or at least about 20°C higher than the glass transition temperature of an otherwise identical film that does not contain the polyvalent metal salt. While not intended to be theoretically bound, it is believed that increasing the polyvalent metal salt content of the film can increase the crosslinking of PVOH chains and increase the energy (i.e., temperature) required to bring the film into an amorphous state.

[0052] The polyvalent metal salt can be provided in an amount sufficient to increase the second glass transition temperature (i.e., the "dry" glass transition temperature, or Tg2) of the film by at least 10°C compared to the second glass transition temperature of an otherwise identical film that does not contain the polyvalent metal salt. For example, the film of the present disclosure may have a second glass transition temperature that is at least about 10°C higher, or at least about 20°C, or about 30°C, or about 40°C, or about 50°C, or about 60°C, or about 70°C higher than the second glass transition temperature of an otherwise identical film that does not contain the polyvalent metal salt.

[0053] As used herein, and unless otherwise specified, “glass transition temperature,” “a glass transition temperature,” and “the glass transition temperature” refer to the first glass transition temperature, Tg, i.e., the glass transition temperature of the hydrated film.

[0054] The polyvalent metal salt can be provided in an amount sufficient to increase the Young's modulus of the film by at least about 10%, at least about 20%, at least about 30%, at least about 50%, at least about 70%, or at least about 90% compared to the Young's modulus of a otherwise identical film that does not contain the polyvalent metal salt. While not intended to be bound by theory, it is believed that increasing the polyvalent metal salt content of the film can increase the crosslinking of PVOH chains, reduce the mobility of the polymer, and provide a stiffer (i.e., higher Young's modulus) film. The films of this disclosure have a Young's modulus of about 40 to about 1000 N / mm². 2 , or approximately 50 to 500 N / mm 2 , or approximately 60 to 300 N / mm 2 , or approximately 100 to approximately 200 N / mm 2 It can have a Young's modulus within the range.

[0055] Polyvalent metal salts can be provided in amounts sufficient to reduce the film's decay time by at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50%. While not intended to be bound by theory, it is believed that incorporating metal salts containing inorganic anions into water-soluble films increases the film's ability to retain water and makes the film more easily biodegradable in water.

[0056] Polyvalent metal salts can be provided in amounts sufficient to reduce the dissolution time of the film by at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50%. While not intended to be bound by theory, it is believed that incorporating metal salts containing inorganic anions into water-soluble films can increase the film's ability to retain water and make the film readily soluble in water.

[0057] Polyvalent metal salts can be provided in water-soluble films in amounts ranging from approximately 1 PHR to approximately 30 PHR, or approximately 2 PHR to approximately 25 PHR, or approximately 3 PHR to approximately 20 PHR, or approximately 5 PHR to approximately 15 PHR, or approximately 6 PHR to approximately 12 PHR, for example, in amounts less than approximately 30 PHR, less than approximately 20 PHR, or less than approximately 15 PHR. While not intended to be theoretically bound, it is believed that as the amount of polyvalent metal salt in the film decreases, for example below 1 PHR, the degree to which the polyvalent metal salt affects crystallinity decreases accordingly, and the benefits to the film's thermal properties diminish. Furthermore, while not intended to be theoretically bound, it is believed that as the amount of polyvalent metal salt in the film increases, for example above 30 PHR, the thermal properties can continue to improve, but the physical strength of the film may be affected, partly due to the low polymer content of the film. Furthermore, it is believed that as the amount of polyvalent metal salts in the film increases, components of the film may begin to separate from the bulk film and accumulate on the film surface. For example, as the polyvalent metal salt content of the film increases, one or more plasticizers (including, but not limited to, polyol or sugar alcohol plasticizers as described herein) may begin to "bleed" from the bulk film to the film surface. The accumulation of plasticizers on the film surface may result in a film with an undesirable sticky surface. Such stickiness can be compensated for, for example, by adding an anti-blocking agent to the film, for example, by providing the anti-blocking agent as part of the film itself, and / or by directly applying the anti-blocking agent to the film surface, which allows for an increase in polyvalent metal salt content and results in improved thermal properties without being adversely affected by the bleeding of plasticizers from the bulk film.

[0058] The water-soluble film may contain polyvalent salts and monovalent metal salts. The monovalent metal salt may contain a monovalent cation selected from the group consisting of lithium, sodium, potassium, and combinations thereof. The monovalent cation may be lithium. The monovalent metal salt may contain any inorganic or organic anion disclosed herein.

[0059] The metal salt may be a lithium salt containing an inorganic anion. Generally, the amount of lithium salt in the film may be any amount sufficient to improve one or more film properties compared to a film that is otherwise identical and does not contain lithium salt. Such film properties may include, but are not limited to, enthalpy of melting, enthalpy of crystallization, glass transition temperature, decay time, and dissolution time. The lithium salt may be present in the film in an amount sufficient to reduce the enthalpy of melting of the film by at least about 20% compared to the enthalpy of melting of a film that is otherwise identical and does not contain lithium salt. For example, the lithium salt may be present in an amount sufficient to reduce the enthalpy of melting of the film by at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 75% compared to the enthalpy of melting of a film that is otherwise identical and does not contain lithium salt.

[0060] The lithium salt can be present in the film in an amount sufficient to reduce the crystallization enthalpy of the film by at least about 20% compared to the crystallization enthalpy of a film otherwise identical without the lithium salt. For example, the lithium salt can be provided in an amount sufficient to reduce the crystallization enthalpy of the film by at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 75% compared to the crystallization enthalpy of a film otherwise identical without the lithium salt.

[0061] The lithium salt can be provided in an amount sufficient to increase the glass transition temperature of the film by at least about 5°C compared to the glass transition temperature of a film otherwise identical without the lithium salt. For example, a film of the present disclosure containing a lithium salt may have a glass transition temperature at least about 5°C higher, at least about 10°C higher, at least about 15°C higher, or at least about 20°C higher than the glass transition temperature of a film otherwise identical without the lithium salt.

[0062] The lithium salt can be provided in an amount sufficient to reduce the decay time of the film by at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% compared to the decay time of an otherwise identical film that does not contain the lithium salt.

[0063] The lithium salt can be provided in an amount sufficient to reduce the dissolution time of the film by at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% compared to the dissolution time of a film that is otherwise identical and does not contain lithium salt.

[0064] Lithium salts can be present in the film in amounts ranging from approximately 1 PHR to approximately 30 PHR, or approximately 2 PHR to approximately 25 PHR, or approximately 3 PHR to approximately 20 PHR, or approximately 5 PHR to approximately 15 PHR, or approximately 6 PHR to approximately 12 PHR, or approximately 2 PHR to approximately 10 PHR, for example, in the range of less than approximately 30 PHR, less than approximately 20 PHR, or less than approximately 15 PHR. While not intended to be constrained by theory, it is believed that as the amount of lithium salt in the film decreases, the benefit of lithium salts to the film's thermal properties decreases. Furthermore, while not intended to be constrained by theory, as the amount of lithium salt in the film increases, thermal properties can continue to improve, but the physical strength of the film may be affected due to a partial reduction in the film's polymer content.

[0065] secondary component Water-soluble films containing the resins disclosed herein include, but are not limited to, plasticizers, plasticizer compatibilizers, surfactants, lubricants, release agents, fillers, bulking agents, crosslinking agents, antiblocking agents, antioxidants, tackiness reducers, defoaming agents, nanoparticles such as layered silicate-type nanoclay (e.g., sodium montmorillonite), bleaching agents (e.g., sodium metabisulfite, sodium bisulfite, etc.), bittering agents (e.g., denatonium benzoate, denatonium benzoate, etc.). Other auxiliary and processing aids may be contained in amounts suitable for these intended purposes, such as denatonium salts (including nium saccharides and denatonium chloride; sucrose octaacetate; quinine; flavonoids (such as quercetin and naringen; and quasinoids (such as quacin and brucin)), and aversive agents (e.g., capsaicin, piperine, allyl isothiocyanate, and resiniferatoxin), as well as other functional components. Films containing plasticizers are particularly intended. Water-soluble films may contain surfactants, antioxidants, bittering agents, soil-release polymers, anti-re-adhesion aids, chelating agents, builders, fragrances, or combinations thereof. The amount of the auxiliary agent may be, for example, individually or collectively, up to about 50% by weight, 20% by weight, 15% by weight, 10% by weight, 5% by weight, 4% by weight, and / or at least 0.01% by weight, 0.1% by weight, 1% by weight, or 5% by weight.

[0066] plasticizer Plasticizers are liquids, solids, or semi-solids added to materials (usually resins or elastomers) to make them more flexible, more pliable (by reducing the glass transition temperature of the polymer), and easier to process. At low levels of plasticizer, films may become brittle, difficult to process, or prone to breakage. At high levels of plasticizer, films may become too soft, too weak, or difficult to process for their desired use. Water is recognized as a very efficient plasticizer for PVOH and other polymers, including but not limited to water-soluble polymers; however, the volatility of water limits its usefulness because polymer films need to have at least some degree of resistance (robustness) to a variety of ambient conditions, including low and high relative humidity. Therefore, as used herein, the term “plasticizer” does not include water.

[0067] In general, with respect to the water-soluble films of the present disclosure, which contain polyvalent metal salts, the water-soluble films may further contain plasticizers. Examples of plasticizers include, but are not limited to, polyols, sugar alcohols, polyethers, amines, or mixtures thereof. For example, the plasticizer may be selected from the group consisting of polyols, sugar alcohols, polyethers, amines, or combinations thereof. Examples of plasticizers include, but are not limited to, glycerol, diglycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol up to 400 MW, neopentyl glycol, 1,2-propylene glycol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, trimethylolpropane, polyether polyols, isomalt, maltitol, sorbitol, xylitol, erythritol, adonitol, dalcitol, pentaerythritol, mannitol, ethanolamine, and mixtures thereof. The plasticizers do not contain divalent metals.

[0068] The total amount of non-aqueous plasticizer may be in the range of approximately 10 to 50 parts by weight (PHR) per 100 parts of PVOH resin, or approximately 10 to 45 PHR, or approximately 15 to 45 PHR, or approximately 15 to 40 PHR, or approximately 17 to 40 PHR, or approximately 20 to 40 PHR, or approximately 25 to 40 PHR, or approximately 25 to 35 PHR, or approximately 25 to 30 PHR.

[0069] surfactants Surfactants for use in water-soluble films are well known in the art. Optionally, surfactants are included to help disperse the resin solution during casting in order to form the film. Suitable surfactants include, but are not limited to, nonionic, cationic, anionic, and zwitterionic types. Suitable surfactants include, but are not limited to, propylene glycol, diethylene glycol, monoethanolamine, polyoxyethylene-modified polyoxypropylene glycol, alcohol ethoxylates, alkylphenol ethoxylates, tertiary acetylene glycol, and alkanolamides (nonionic), polyoxyethylene-modified amines, quaternary ammonium salts, and quaternary polyoxyethylene-modified amines (cationic), alkali metal salts of higher fatty acids containing about 8 to 24 carbon atoms, alkyl sulfates, alkyl polyethoxylate sulfates, and alkylbenzene sulfonates (anionic), as well as amine oxides, N-alkyl betaines, and sulfobetaines (zwitterionic). Other suitable surfactants include dialkyl sulfosuccinates, lactyl fatty acid esters of glycerin and propylene glycol, lactyl esters of fatty acids, sodium alkyl sulfates, polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80, alkyl polyethylene glycol, lecithin, acetylated fatty acid esters of glycerin and propylene glycol, sodium lauryl sulfate, acetylated esters of fatty acids, myristyldimethylamine oxide, trimethyl tallowalkylammonium chloride, quaternary ammonium compounds, salts thereof, and any combination of the above. Surfactants may include those selected from the group consisting of polyoxyethylene-modified polyoxypropylene glycol, alcohol ethoxylates, alkylphenol ethoxylates, tertiary acetylene glycols and alkanolamides, polyoxyethylene-modified amines, quaternary ammonium salts and quaternary polyoxyethylene-modified amines, and amine oxides, N-alkyl betaines, sulfobetaines, and combinations thereof.

[0070] The amount of surfactant in a water-soluble film may be in the range of approximately 0.1% to 8.0% by weight, or approximately 1.0% to 7.0% by weight, or approximately 3% to 7% by weight, or approximately 5% to 7% by weight, or approximately 0.1% to 2.5% by weight. Too little surfactant may occasionally result in a cast film with holes, while too much surfactant may result in a film that is slippery or oily due to the excess surfactant present on the film surface.

[0071] Lubricant / Removal Agent Suitable lubricants / release agents for use in water-soluble films as described herein include, but are not limited to, fatty acids and their salts, fatty alcohols, fatty esters, fatty amines, fatty amine acetates, and fatty amides. Preferred lubricants / release agents are fatty acids, fatty acid salts, and fatty amine acetates. The amount of lubricant / release agent in the water-soluble film may be in the range of about 0.02% to about 1.5% by weight, and optionally, about 0.1% to about 1% by weight.

[0072] defoaming agent The water-soluble films disclosed herein may also contain defoamers. Defoamers can help fuse bubbles. Suitable defoamers for use in the water-soluble films according to this disclosure include, but are not limited to, hydrophobic silica, such as fine-grained silicon dioxide, siloxane, silicone ether, or fumed silica, and Foam Blast® defoamers available from Emerald Performance Materials, including the proprietary non-mineral oil defoamers Foam Blast® 327, Foam Blast® UVD, Foam Blast® 163, Foam Blast® 269, Foam Blast® 338, Foam Blast® 290, Foam Blast® 332, Foam Blast® 349, Foam Blast® 550, and Foam Blast® 339. Suitable defoaming agents also include Foam-A-Tac(registered trademark) 6, Foam-A-Tac(registered trademark) 110, Foam-A-Tac(registered trademark) 213, Foam-A-Tac(registered trademark) 251, Foam-A-Tac(registered trademark) 402, Foam-A-Tac(registered trademark) 407, Foam-A-Tac(registered trademark) 414, Foam-A-Tac(registered trademark) 417, Fo Examples of Foam-A-Tac® defoamers available from Enterprise Specialty Products include, but are not limited to, am-A-Tac® 435, Foam-A-Tac® 612, Foam-A-Tac® 613, Foam-A-Tac® 615, Foam-A-Tac® 642, Foam-A-Tac® 643, Foam-A-Tac® 943, and Foam-A-Tac® PCI. For example, the defoamer can be used in amounts of 0.5 PHR or less, such as 0.05 PHR, 0.04 PHR, 0.03 PHR, 0.02 PHR, or 0.01 PHR.

[0073] Antioxidant The water-soluble films disclosed herein may further contain, for example, antioxidants as chloride scavengers. Suitable antioxidants / chloride scavengers include, for example, sulfites, bisulfites, thiosulfates, iodides, nitrides, carbamates, ascorbetes, and combinations thereof. Antioxidants may include propyl gallate (PGA), citric acid (CA), sodium metabisulfite (SMBS), carbamates, ascorbetes, or combinations thereof. Antioxidants may be present in the film in amounts ranging from about 0.25 to about 1.5 PHR, for example, about 0.25 PHR, about 0.30 PHR, about 0.35 PHR, about 0.40 PHR, about 0.45 PHR, about 0.5 PHR, about 0.75 PHR, about 1.0 PHR, about 1.25 PHR, or about 1.5 PHR.

[0074] Filler Fillers that may be included in water-soluble films include bulking agents, fillers, anti-blocking agents, tackiness reducers, and combinations thereof. Suitable fillers for use in water-soluble films disclosed herein include, but are not limited to, starch, modified starch, cross-linked polyvinylpyrrolidone, cross-linked cellulose, microcrystalline cellulose, silica, metal oxides, calcium carbonate, talc, mica, stearic acid and its metal salts, such as magnesium stearate. The amount of filler / filler / anti-blocking agent / tackiness reducer in a water-soluble film may be, for example, in the range of about 1% to about 6% by weight, or about 1% to about 4% by weight, or about 2% to about 4% by weight, or about 1 PHR to about 6 PHR, or about 1 PHR to about 4 PHR, or about 2 PHR to about 4 PHR.

[0075] Water-soluble films may contain 2 PHR or more of fillers (e.g., 2 PHR to 6 PHR or 2 PHR to 4 PHR). For example, a film may contain 2 PHR or more of fillers (e.g., 2 PHR to 6 PHR or 2 PHR to 4 PHR), and the fillers may include bulking agents, anti-blocking agents, or combinations thereof. While not intended to be theoretically bound, it is thought that including 2 PHR or more of fillers (e.g., 2 PHR to 6 PHR or 2 PHR to 4 PHR) may be useful in preventing the leaching or migration of plasticizers from the film when plasticizers are included in amounts of 30 PHR or more, for example, in the range of 30 PHR to 50 PHR.

[0076] Water-soluble films may be binder-free. As used herein, “binder” refers to a polymer that can improve the bonding of two film layers to each other. Binders may be components of film layers, including multilayer films. Typical binders include carboxymethylcellulose, as well as modified celluloses such as alkyl and hydroxyalkyl modified cellulose and methylcellulose, and natural gums such as gum arabic. Water-soluble films of this disclosure may be cellulose, modified cellulose, and natural gum-free. As used herein and unless otherwise specified, a water-soluble film is “binder-free” and / or “cellulose, modified cellulose, and natural gum-free” if the film contains less than 0.05% by weight of binder or cellulose, modified cellulose, and natural gum, respectively, based on the total weight of the film.

[0077] An anti-blocking agent (e.g., SiO2 and / or stearic acid) may be present in the film in amounts of at least 0.1 PHR, or at least 0.5 PHR, or at least 1 PHR, or within the range of about 0.1 to 5.0 PHR, or about 0.1 to about 3.0 PHR, or about 0.4 to 1.0 PHR, or about 0.5 to about 0.9 PHR, or about 0.5 to about 2 PHR, or about 0.5 to about 1.5 PHR, or 0.1 to 1.2 PHR, or 0.1 to 2.7 PHR, for example, 0.5 PHR, 0.6 PHR, 0.7 PHR, 0.8 PHR, or 0.9 PHR.

[0078] Suitable median particle size values ​​for the blocking inhibitor include a range of approximately 3 or 4 microns to approximately 11 microns, or approximately 4 to approximately 8 microns, or approximately 5 to approximately 6 microns, for example, a median of 5, 6, 7, 8, or 9 microns.

[0079] Aversive agents Aversive agents may be incorporated into water-soluble films or applied as a coating to water-soluble films. Aversive compounds such as bittering agents or irritants may be added as deterrents against ingestion of the film by children or animals. Bittering agents impart a bitter taste to the composition to which they are added. Suitable bittering agents include denatonium salts (e.g., denatonium benzoate, denatonium saccharide, denatonium chloride), sucrose octaacetate, quinine, flavonoids (e.g., quercetin, naringen), and quasinoids (e.g., quacin, brucine). Irritants impart a sharp, stinging taste when ingested and a burning sensation when applied topically to the skin. Suitable irritants include capsaicin, piperine, allyl isothiocyanate, and resiniferatoxin. The preferred level of incorporation varies depending on the specific bittering agent or irritant material. As will be understood by those skilled in the art, the aversive component should be incorporated at a level high enough to impart an unpleasant taste or sensation, but at a level low enough to avoid potential toxicity from the aversive agent itself. The aversive agent may be diluted from its commercially available form or mixed with a solvent to facilitate mixing with other water-soluble film components or application as a coating to a water-soluble film. Such solvents may be selected from water, low molecular weight alcohols (such as methanol or ethanol), or plasticizers disclosed herein.

[0080] How to make a film Water-soluble films containing water-soluble resins disclosed herein can be prepared by any preferred method. Processes for preparing water-soluble films and pouches include solvent casting, blow molding, extrusion, and blow extrusion, which are known in the art. Processes for solvent casting of PVOH are well known in the art. For example, in a film-forming process, the polyvinyl alcohol resin and secondary additives are dissolved in a solvent, typically water, metered and supplied onto a surface, substantially dried (or force-dried) to form a cast film, and then the resulting cast film is removed from the casting surface. The process can be carried out in batches, but is more efficient in a continuous process.

[0081] Conventional practice in forming continuous films of polyvinyl alcohol involves metering and supplying a solution onto a moving casting surface, such as a continuously moving metal drum or belt, causing the solvent to be substantially removed from the liquid, thereby forming a self-supporting cast film, which is then peeled off the resulting cast film from the casting surface. The solution may optionally be metered or coated onto a carrier film, release liner, or removable backing, so that, after solvent removal, the resulting cast film or coating can be separated from the carrier film, release liner, or removable backing (e.g., immediately after drying, or at a later point, e.g., before use), or may remain attached to the carrier film, release liner, or removable backing.

[0082] The films disclosed herein can be manufactured, for example, by solvent casting using a solvent band casting system. The system may include a tank for mixing and / or storing a polymer solution with an optional secondary additive, for use with a band casting machine having at least first and second rotating drums that apply tension to a continuous band (e.g., a metal band) so that it moves with the rotation of the drum. A sheet die can apply the polymer solution from the tank to the metal band, and a drying chamber surrounding at least a portion of the metal band downline of the sheet die is used to remove the solvent from the polymer solution as it moves with a thin sheet on the metal band. In addition, a release coating can be used to provide one or more advantages to the film and / or process. For example, the release coating can substantially reduce or eliminate air bubbles in the manufactured polymer film, or the release coating can improve the ease of peeling the manufactured film from the casting surface. A roll coater release coating applicator communicating with a supply of the release coating and a portion of the band can transfer the fluid release coating to the casting surface before applying the polymer solution to the band. Suitable solvent band casting systems and related materials are further described in U.S. Patent Applications Publication Nos. 2006 / 0081176A1 and 2007 / 0085234A1, the disclosures of which are incorporated herein by reference in their entirety.

[0083] In general, the casting surface can be any suitable substrate for manufacturing polymer films, as is the case for those skilled in the art. The substrate can be a casting roller or drum, a casting belt, or a combination thereof. As used herein, the substrate is used to manufacture polymer films from a polymer resin or a polymer resin solution. The substrate includes a substrate surface, and the substrate surface is coated with a release coating. The polymer resin solution can be cast onto the substrate while the substrate is moving, for example, rotating. The substrate can be a casting drum. The substrate can be a casting belt. The substrate can include stainless steel and, optionally, may have a stainless steel surface. The substrate can optionally include plated stainless steel, such as chromium plating, nickel plating, zinc plating, or a combination thereof.

[0084] Optionally, the water-soluble film may be a self-supporting film consisting of one or more similar layers.

[0085] Optionally, the water-soluble film may be a foamed film, i.e., a film containing multiple macroscopic and / or microscopic voids. A foamed film can be produced by casting a layer of foamed resin solution (i.e., a resin solution in which air or another gas is incorporated) and drying the foamed resin solution layer, thereby providing a film containing multiple macroscopic and / or microscopic voids.

[0086] Thermal properties The films of this disclosure may generally be characterized by one or more thermal properties, including, but not limited to, a glass transition temperature, melting temperature, crystallization temperature, enthalpy of melting, and enthalpy of crystallization. Methods for determining these thermal properties are known in the art, for example, by differential scanning calorimetry (DSC).

[0087] In general, the water-soluble films of this disclosure may differ in one or more thermal properties from water-soluble films that are otherwise identical and do not contain metal salts. Such differences in thermal properties may offer advantages in applications such as thermoforming or dissolution in cold water, which are related to the thermal properties of the film.

[0088] The water-soluble films of this disclosure may have an enthalpy of melting that is at least 20%, at least 25%, at least 40%, at least 50%, or at least 75% lower than that of a otherwise identical film that does not contain metal salts. Alternatively, the water-soluble films of this disclosure may not exhibit melting transitions as determined by DSC and may have no enthalpy of melting.

[0089] The water-soluble films of this disclosure may have a crystallization temperature of at least 5°C, at least 10°C, at least 20°C, at least 30°C, or at least 40°C below the crystallization temperature of a otherwise identical film that does not contain metal salts. Alternatively, the water-soluble films of this disclosure may not exhibit a crystallization temperature as determined by DSC.

[0090] The water-soluble films of this disclosure may have a crystallization enthalpy of less than approximately 50 J / g, or less than approximately 30 J / g, or less than approximately 20 J / g, or less than approximately 15 J / g, or less than approximately 10 J / g, or less than approximately 1 J / g, or 0 J / g (i.e., undetectable by DSC). The crystallization enthalpy of the water-soluble films of this disclosure may be less than that of a otherwise identical water-soluble film that does not contain metal salts. Alternatively, the water-soluble films of this disclosure may not exhibit a crystallization enthalpy as determined by DSC.

[0091] Although not intended to be bound by theory, reducing the melting enthalpy and / or crystallization enthalpy of a water-soluble film can provide a film having improved thermoformability, e.g., a film that can be thermoformed at a temperature lower than the temperature typically required to thermoform the film, e.g., a temperature less than 90 °C.

[0092] Mechanical properties The water-soluble films of the present disclosure can be characterized by a tensile strength determined by the tensile strength test described herein. Generally, the water-soluble films of the present disclosure have a tensile strength of at least about 20 N / mm 2 or at least about 25 N / mm 2 or at least about 30 N / mm 2 The water-soluble films of the present disclosure can have a tensile strength in the range of from about 20 to about 200 N / mm 2 from about 20 to about 100 N / mm 2 from about 20 to about 50 N / mm 2 from about 25 to about 200 N / mm 2 from about 25 to about 100 N / mm 2 from about 25 to about 50 N / mm 2 from about 30 to about 200 N / mm 2 from about 30 to about 100 N / mm 2 or from about 30 to about 50 N / mm 2 Generally, higher tensile strength values are desirable as they correspond to stronger pouch seals, especially if the film is the sealing limit or weakest element.

[0093] The water-soluble films of the present disclosure can be characterized by a Young's modulus when determined by the tensile strength test described herein. Generally, the water-soluble films of the present disclosure have a Young's modulus of at least about 40 N / mm 2 or about 50 N / mm 2 or about 60 N / mm 2 or about 100 N / mm 2 or about 200 N / mm 2 The water-soluble films can have a Young's modulus in the range of from about 40 to about 1000 N / mm 2 from about 40 to about 500 N / mm2 , about 40~300N / mm 2 , about 40 to about 200N / mm 2 , about 50 to about 1000N / mm 2 , about 50~500N / mm 2 , about 50~300N / mm 2 , about 50~200N / mm 2 , about 60~about 1000N / mm 2 , about 60~500N / mm 2 , about 60 to about 300N / mm 2 , about 60~200N / mm 2 , about 100 to about 1000N / mm 2 , about 100 to about 500N / mm 2 , about 100 to about 300N / mm 2 , or approximately 100 to approximately 200 N / mm 2 It can be characterized by having a Young's modulus within the range of . In embodiments in which the metal salt includes a lithium salt, the water-soluble film has a Young's modulus of approximately 5 N / mm 2 ~Approximately 100 N / mm 2 , about 10N / mm 2 ~about 50N / mm 2 , or approximately 20 N / mm 2 ~Approx. 30N / mm 2 It can be characterized by having a Young's modulus within a certain range. Generally, Young's modulus is a measure of the stiffness of a film, and a higher Young's modulus indicates increased stiffness.

[0094] While not intended to be constrained by theory, it is believed that the addition of metal salts to water-soluble films can at least partially alter the thermal properties of the film by disrupting the crystalline structure of PVOH in the film. Furthermore, it is believed that such changes in the properties of PVOH films can allow the film to be thermoformed at a lower minimum temperature compared to the minimum temperature required to thermoform an otherwise identical film that does not contain polyvalent metal salts.

[0095] The water-soluble films of this disclosure may be characterized by elongation at break (i.e., strain at break) as determined according to the elongation at break test described herein. Generally, the water-soluble films of this disclosure have a strain at break of at least about 25%, for example, at least about 50%, at least about 75%, at least about 100%, at least about 125%, at least about 150%, at least about 175%, at least about 200%, or at least about 225%. The water-soluble films of this disclosure may have strains of about 25% to about 700%, 25% to about 600%, about 25% to about 500%, about 25% to about 250%, about 50% to about 700%, about 50% to about 600%, about 50% to about 500%, about 50% to about 400%, about 50% to about 300%, about 50% to about 250%, and about 100%. ~700%, ~100%~600%, ~100%~500%, ~100%~400%, ~100%~300%, ~100%~250%, ~150%~700%, ~150%~600%, ~150%~500%, ~150%~400%, ~150%~300%, ~ It can have an elongation at break within the range of 150% to approximately 250%, approximately 200% to approximately 700%, approximately 200% to approximately 600%, approximately 200% to approximately 500%, approximately 200% to approximately 300%, approximately 250% to approximately 700%, approximately 250% to approximately 600%, approximately 250% to approximately 500%, approximately 250% to approximately 400%, approximately 250% to approximately 350%, approximately 300% to approximately 700%, 300% to approximately 600%, approximately 300% to approximately 500%, approximately 300% to approximately 450%, approximately 350% to approximately 700%, approximately 350% to approximately 500%, approximately 350% to approximately 450%, or approximately 350% to approximately 400%, or approximately 400% to approximately 500%. Generally, increased elongation at break indicates a film that can withstand greater deformation before mechanical failure.

[0096] The water-soluble films of this disclosure may have dissolution and disintegration times of less than approximately 300 seconds, less than approximately 250 seconds, less than approximately 200 seconds, less than approximately 150 seconds, less than approximately 100 seconds, or less than approximately 50 seconds, as measured by the dissolution and disintegration tests described herein. The water-soluble films of this disclosure may have disintegration times less than those of otherwise identical films that do not contain metal salts. The water-soluble films of this disclosure may have dissolution times less than those of otherwise identical films that do not contain metal salts.

[0097] The water-soluble films of this disclosure can exhibit faster decay and / or dissolution in brine compared to otherwise identical water-soluble films that do not contain metal salts. When the water-soluble films of this disclosure are provided in a thickness of about 76 microns, they can have a decay time of at least 30%, at least 40%, at least 45%, or at least 50% of the decay time of otherwise identical films that do not contain polyvalent salts, and the decay time is measured in an aqueous solution of 3.5% by weight of sodium chloride at 5°C according to the MonoSol Test Method MSTM 205. When the water-soluble films of this disclosure are provided in a thickness of about 76 microns, they can have a dissolution time of at least 30%, at least 40%, at least 45%, or at least 50% of the dissolution time of otherwise identical films that do not contain polyvalent salts, and the dissolution time is measured in an aqueous solution of 3.5% by weight of sodium chloride at 5°C according to the MonoSol Test Method MSTM 205.

[0098] water soluble articles The film is useful for creating articles and / or pouches for containing compositions, such as cleaning compositions. The composition contained in the pouch may take any form, such as a powder, gel, paste, liquid, tablet, or any combination thereof. The film is also useful for any other applications where improved wetting treatment and less cold water residue are desirable. The film forms the outer surface of at least one side wall of the article and / or pouch, optionally the entire article and / or pouch, and preferably the outer surface of at least one side wall.

[0099] The films described herein may also be used to produce articles and / or pouches having two or more compartments, either made from the same film or in combination with films of other polymer materials. Additional films can be obtained, for example, by casting, blow molding, extrusion molding, or blow extrusion molding of the same or different polymer materials known in the art. Suitable polymers, copolymers, or derivatives thereof for use as additional films include polyvinyl alcohol, polyvinylpyrrolidone, polyalkylene oxide, polyacrylic acid, cellulose, cellulose ether, cellulose ester, celluloseamide, polyvinyl acetate, polycarboxylic acids and salts, polyamino acids, or peptides, polyamides, polyacrylamide, maleic acid / acrylic acid copolymers, polysaccharides including starch and gelatin, natural gums such as xanthan gum, and carrageenan. For example, the polymer may be selected from polyacrylates and water-soluble acrylate copolymers, methylcellulose, sodium carboxymethylcellulose, dextrin, ethylcellulose, hydroxyethylcellulose, hydroxypropyl methylcellulose, maltodextrin, polymethacrylate, and combinations thereof, or from polyvinyl alcohol, polyvinyl alcohol copolymers and hydroxypropyl methylcellulose (HPMC), and combinations thereof. For example, the polymer level in the packet material, e.g., the PVOH copolymer described above, may be at least 60%, as described above.

[0100] In some embodiments, the films of this disclosure are cellulose and modified cellulose-free. As used herein, and unless otherwise specified, “cellulose and modified cellulose-free” means a film having a cellulose and / or modified cellulose content of less than 0.05% based on the total weight of the film.

[0101] The articles and / or pouches of this disclosure may include at least one sealed compartment. Thus, the articles and / or pouches may comprise one or more compartments. A water-soluble pouch or sachet may be formed from two layers of water-soluble polymer films sealed at the interface, or from a single film folded and sealed on itself. One or both of the films may include the PVOH films described above. The films define the internal article and / or pouch container volume for containing any desired composition for release into an aqueous environment.

[0102] The volume of the pouch container is not particularly limited. The volume of the pouch container may be, for example, 25 mL or less. The volume of the pouch container may be less than 25 mL. The volume of the pouch container may be less than 50 mL.

[0103] The compositions for use in the pouch are not particularly limited. In the case of a pouch having multiple compartments, each compartment may contain the same and / or different compositions, but is not limited to those containing an automatic dishwashing (ADW) composition. The compositions may be liquids, solids, and combinations thereof (e.g., solids suspended in a liquid), but are not limited to any other suitable form. The pouch may have first, second, and third compartments, each of which may contain a different first, second, and third composition. Liquid detergents are particularly considered. Liquid compositions containing citric acid, solid compositions containing citric acid, and compositions containing citric acid itself, but not limited to those containing citric acid, are particularly intended.

[0104] The compartments of a multi-compartment article and / or pouch may be the same or different in size and / or volume. The compartments of the multi-compartment article and / or pouch may be separated or joined in any preferred manner. Second and / or third and / or subsequent compartments may be superimposed on the first compartment. A third compartment may be superimposed on the second compartment, and then the second compartment may be superimposed on the first compartment in a sandwich configuration. Alternatively, the second and third compartments may be superimposed on the first compartment. However, it is equally conceivable that the first, second, and optionally third, and subsequent compartments may be mounted side by side. The compartments may be packaged in a chain, and each compartment may be individually separable by perforations. Thus, each compartment may be individually torn from the rest of the chain by the end user, for example, to pre-treat or post-treat a cloth using a composition from a particular compartment. The first compartment can be surrounded by at least a second compartment, for example, in a tire and rim configuration, or in a pouch-in-pouch configuration.

[0105] The articles and / or pouches of the present disclosure may comprise one or more different films. For example, with respect to a single-compartment packet, the packet may be made of one wall which is folded over itself and sealed at the edge, or alternatively, two walls which are sealed together at the edges. With respect to a multi-compartment packet, the articles and / or packets may be made of one or more films such that any given packet compartment may comprise walls made of a single film or multiple films having different compositions. A multi-compartment article and / or pouch may comprise at least three walls: an upper outer wall, a lower outer wall, and a partition wall. The upper and lower outer walls are generally opposite each other and form the exterior of the article and / or pouch. The partition wall is inside the article and / or pouch and is generally fixed to the opposite outer wall along the sealing line. The partition wall separates the interior of the multi-compartment article and / or pouch into at least a first compartment and a second compartment.

[0106] A single compartment or a group of sealed compartments can contain a certain composition. Each of the compartments may contain the same or different compositions. The composition can be selected from liquids, solids, or combinations thereof.

[0107] This disclosure provides a unit-dose article comprising at least one compartment and optionally a composition contained within the compartment, wherein at least one wall of the compartment comprises a water-soluble film of this disclosure.

[0108] Contents of articles and / or pouches In general, the water-soluble articles of this disclosure can contain household care products, personal care products, or non-household care products. A unit dose article may contain a composition contained within a compartment, and the composition may contain an oxidizing agent. The oxidizing agent may include hypochlorite salts, chloramines, chlorinated isocyanurates, brominated isocyanurates, chlorates, bromates, perchlorates, perbromates, calcium hydroxylates, calcium chlorides, parkerbonates, perborates, periodates, persulfates, permanganates, chromates, dichromates, nitrates, nitrites, peroxides, ketone peroxides, peroxy acids, inorganic acids, or combinations thereof. The oxidizing agent may include hypochlorite salts, chloramines, chlorinated isocyanurates, calcium hydroxylates, calcium chlorides, parkerbonates, perborates, persulfates, permanganates, peroxides, peroxy acids, or combinations thereof.

[0109] In general, contact between a water-soluble article containing a polymer film and a liquid or solid composition packaged within the article can result in the migration of one or more components of the composition to the polymer film. This migration of materials from the composition to the polymer film can affect the properties of the polymer film, including, but not limited to, solubility and mechanical properties. In particular, for water-soluble articles containing a PVOH-based film and a composition containing an organic acid such as citric acid, a portion of the organic acid can migrate to the PVOH-based film, and the organic acid can partially crosslink the PVOH resin containing the film. This added crosslinking can affect the film properties, for example, by increasing the dissolution time of the film or making the film more brittle and susceptible to premature fracture, effects that may be undesirable for certain applications. As described herein, adding metal salts to PVOH-based films can mitigate such effects. While not intended to be theoretically bound, it is believed that cations from metal salts present in the PVOH-based film can modulate acid groups from the organic acid migrated to the film, reducing the availability of acid groups to crosslink the PVOH.

[0110] Method of manufacturing an item Articles such as pouches or packets may be manufactured using any suitable apparatus and methods. For example, a single-compartment pouch may be manufactured using vertical forming and filling, horizontal forming and filling, or rotary drum filling techniques, which are commonly known in the art. Such processes may be continuous or intermittent. The film may be wetted and / or heated to increase its malleability. The method may also involve the use of vacuum to draw the film into a suitable mold. The vacuum used to draw the film into the mold may be applied for about 0.2 to about 5 seconds, or about 0.3 to about 3 seconds, or about 0.5 to about 1.5 seconds, once the film is placed on the horizontal portion of the surface. This vacuum may provide a negative pressure in the range of, for example, 10 mbar to 1000 mbar, or 100 mbar to 600 mbar.

[0111] The molds from which packets can be produced can have any shape, length, width, and depth, depending on the required dimensions of the pouch. The molds can also vary in size and shape from one another as needed. For example, the final pouch volume may be approximately 5 mL to 300 mL, or approximately 10 mL to 150 mL, or approximately 20 mL to 100 mL, and the size of the molds can be adjusted accordingly.

[0112] thermoforming A thermoformable film is a film that can be formed through the application of heat and force. Thermoforming of a film is the process of heating the film, forming it (for example, in a mold), and then allowing the film to cool so that the film retains its shape, for example, the shape of the mold. Heat can be applied using any suitable means. For example, a film can be heated directly by passing it under a heating element or through hot air before or after it has been supplied onto a surface. Alternatively, a film can be heated indirectly, for example, by heating its surface or by applying a hot article onto the film. A film can be heated using infrared light. A film can be heated to temperatures in the range of about 50°C to about 150°C, about 50°C to about 120°C, about 60°C to about 130°C, about 70°C to about 120°C, or about 60°C to about 90°C. The film may be heated to a temperature within the range of approximately 30°C to 100°C, or approximately 40°C to 100°C, or approximately 50°C to 100°C, or approximately 60°C to 100°C, or approximately 30°C to 90°C, or approximately 40°C to 90°C, or approximately 50°C to 90°C. The film may be heated to a temperature within the range of approximately 30°C to 80°C, or approximately 40°C to 80°C, or approximately 50°C to 80°C, or approximately 60°C to 80°C, or approximately 30°C to 70°C, or approximately 30°C to 60°C, or approximately 30°C to 50°C. Thermoforming can be carried out by one or more of the following processes: manually draping a thermally softened film onto a mold; pressure induction forming (e.g., vacuum forming) of a softened film onto a mold; or automatically high-speed indexing a newly extruded sheet having a precisely known temperature to a forming and trimming station; or by automatic placement, plugging and / or pneumatic stretching and pressure forming of the film.

[0113] Alternatively, the film may be moistened by any suitable means before or after it has been supplied onto a surface, for example, by spraying a wetting agent (including water, a solution of the film composition, a plasticizer for the film composition, or any combination thereof) onto the film, directly, by wetting the surface, or by indirectly applying a wet article to the film.

[0114] Once the film is heated and / or wetted, it can be drawn into a suitable mold, preferably using a vacuum. Filling of the molded film can be achieved by utilizing any preferred means. The most preferred method will depend on the form of the product and the required filling rate. The molded film can be filled by an in-line filling technique. The filled open packets can then be sealed using a second film to form a pouch, by any preferred method. This can be achieved in a continuous, constant motion while in a horizontal position. Sealing can be achieved by continuously supplying a second film, preferably a water-soluble film, over and over the entire open packet, and then sealing the first and second films together, preferably in the region between the molds and therefore between the packets.

[0115] Sealing of water-soluble articles Any suitable method for sealing packets and / or their individual compartments may be used. Non-limiting examples of such means include thermal sealing, solvent welding, solvent or wet sealing, and combinations thereof. Typically, only the area where the seal is formed is treated with heat or solvent. Heat or solvent may be applied by any means, typically on the sealing material and typically only on the area where the seal is formed. When solvent or wet sealing or welding is used, it may be preferable that heat is also applied. A preferred method of wet or solvent sealing / welding includes selectively applying the solvent to the area between the molds or onto the sealing material, for example by spraying or printing onto these areas, and then applying pressure onto these areas to form the seal. For example, sealing rolls and belts (which optionally also provide heat) may also be used.

[0116] The inner film can be sealed to the outer film by solvent sealing. The sealing solution is generally an aqueous solution. The sealing solution may contain water. The sealing solution may contain water and may further contain one or more diols and / or glycols such as 1,2-ethanediol (ethylene glycol), 1,3-propanediol, 1,2-propanediol, 1,4-butanediol (tetramethylene glycol), 1,5-pantanediol (pentamethylene glycol), 1,6-hexanediol (hexamethylene glycol), 2,3-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, various polyethylene glycols (e.g., diethylene glycol, triethylene glycol), and combinations thereof. The encapsulation solution may contain erythritol, slayitol, arabitol, xylitol, ribitol, mannitol, sorbitol, galactitol, fusitol, iditol, inositol, boremitol, isomalt, maltitol, and lactitol.

[0117] The sealing solution can be applied to the interface area of ​​the inner film in any amount suitable for bonding the inner and outer films. As used herein, the term "coating weight" refers to the amount of sealing solution applied to the film in grams of solution per square meter of film. Generally, if the coating weight of the sealing solvent is too low, the film will not adhere properly, increasing the risk of pouch defects at the seams. Furthermore, if the coating weight of the sealing solvent is too high, the risk of solvent migration from the interface area increases, increasing the possibility of etching holes forming on the sides of the pouch. The coating weight window refers to the range of coating weights that can be applied to a given film while maintaining good adhesion and avoiding the formation of etching holes. A wide coating weight window is desirable because it provides a robust seal under a wide range of operations. A suitable coating weight window is at least about 3 g / m². 2 , or at least about 4 g / m 2 , or at least about 5 g / m 2 , or at least about 6 g / m 2 That is the case.

[0118] fiber With respect to the films of this disclosure, the compositions described herein can be used as fiber compositions.

[0119] Fibers having the same composition as the films of this disclosure are also contemplated. Such fibers may include polyvinyl alcohol resins, plasticizers, and metal salts, as described herein. The polyvinyl alcohol resins of the fibers of this disclosure are not particularly limited and may include, for example, one or more polyvinyl alcohol homopolymers, one or more polyvinyl alcohol copolymers, or blends thereof. The fibers may include any of the secondary components disclosed herein for the films of this disclosure. For example, the fibers may include, in amounts suitable for their intended purpose, surfactants, lubricants, release agents, fillers, extenders, crosslinking agents, antiblocking agents, antioxidants, tackiness reducers, defoamers, nanoparticles such as layered silicate-type nanoclay (e.g., sodium montmorillonite), bleaching agents (e.g., sodium metabisulfite, sodium bisulfite, etc.), bittering agents, irritants, or any combination of the foregoing.

[0120] Methods for producing fibers are known in the art. For example, U.S. Patent Application Publication No. 2022 / 0228305A1 describes wet-cooled gel spinning, thermoplastic fiber spinning, and melt-spinning methods for preparing fibers containing water-soluble polymers or blends of water-soluble polymers. Such methods are generally suitable for producing fibers according to the present disclosure.

[0121] The fibers of this disclosure can be used as components of a nonwoven web comprising multiple fibers. A nonwoven web generally refers to an arrangement of fibers joined together, where the fibers are neither woven nor knitted. Generally, the multiple fibers can be arranged in any orientation. The multiple fibers can be arranged randomly (i.e., without orientation). The multiple fibers can be arranged in a unidirectional orientation. The multiple fibers can be arranged in a bidirectional orientation. The multiple fibers may be multidirectional, having different arrangements in different regions of the nonwoven web.

[0122] The Disclosure provides a unit-dose article comprising at least one compartment and optionally a composition contained within the compartment, wherein at least one wall of the compartment comprises a nonwoven web of the Disclosure.

[0123] While not intended to be theoretically bound, it is believed that incorporating metal salts into polyvinyl alcohol resin fibers can benefit fibers or nonwoven webs or other compositions containing fibers, as described herein for films containing polyvinyl alcohol resin and metal salts. Such benefits may include, but are not limited to, improvements in mechanical and thermal properties.

[0124] Conductivity / Resistance The films, fibers, and / or nonwoven webs of this disclosure may undergo an increase in conductivity when exposed to a watery or humid environment. The increase in conductivity of a film can be detected, for example, by measuring the decrease in the overall resistance of the film when exposed to a watery or humid environment. Exposure to a watery or humid environment may include, for example, immersing the film in water or storing the film in an environment with high relative humidity, e.g., relative humidity (RH) above 50%. Water-soluble films without the addition of salts and films of this disclosure may have a resistance of over 60 MΩ (megaohms), or over 40 MΩ, or over 20 MΩ in a dry state (e.g., measured after being adjusted to a high temperature to reduce or remove the moisture content of the film). Advantageously, when exposed to a watery or humid environment, the films of this disclosure may have a resistance of less than 60 MΩ, or less than 40 MΩ, or less than 20 MΩ, or less than 10 MΩ, or less than 5 MΩ, or less than 1 MΩ, or less than 100 kΩ, or less than 50 kΩ, or less than 10 kΩ, or less than 5 kΩ, or less than 1 kΩ. Polymer films, fibers, and / or nonwoven webs whose conductivity and resistance change when exposed to a watery or humid environment may find use in applications such as sensing, flexible electronics, and smart fabrics.

[0125] The films of this disclosure can, advantageously, have a dry resistance (i.e., resistance measured on a sample of the film immediately after the sample has been prepared in a 23°C / 35%RH environment for at least 24 hours, as described herein) that is lower than the resistance of a salt-free water-soluble film. The films of this disclosure can have, for example, a resistance of less than about 60 MΩ, or less than about 50 MΩ, or less than about 40 MΩ, or less than about 30 MΩ.

[0126] The following table lists the articles intended by this disclosure, including their compositional details, physical properties, and potential applications. These examples are included for illustrative purposes only and are not intended to limit the scope of this disclosure. [Table 1]

[0127] Test method Dissolution and disintegration test (MSTM 205) The film can be characterized by or tested for dissolution time and decay time according to MonoSol Test Method 205 (MSTM205), a method known in the art. See, for example, U.S. Patent No. 7,022,656. Apparatus and materials: 600 mL beaker Magnetic stirrer (Labline model number 1250 or equivalent) Magnetic stirring rod (5cm) Thermometer (0~100℃±1℃) Template, stainless steel (3.8cm x 3.2cm) Timer (0-300 seconds, accuracy in seconds) Polaroid 35mm slide mount (or equivalent) MonoSol 35mm slide mount holder (or equivalent) distilled water

[0128] All films to be tested were conditioned for a minimum of 24 hours in an environment of 23°C / 35% relative humidity. For each film to be tested, three test specimens were cut from the film sample, each measuring 3.8 cm × 3.2 cm. When cutting from the film web, the specimens should be cut from equally spaced web areas along the transverse direction of the web. Each test specimen was then analyzed using the following procedure.

[0129] Each test specimen is secured in a separate 35mm slide mount.

[0130] Fill a beaker with 500 mL of distilled water. Measure the water temperature with a thermometer and, if necessary, heat or cool the water to maintain the desired temperature for the test. Unless otherwise specified, disintegration and dissolution tests were performed in water at approximately 5°C (approximately 41°F).

[0131] Mark the height of the water column. Place the magnetic stirrer on the base of the holder. Place the beaker on the magnetic stirrer, add the magnetic stirring rod to the beaker, turn on the stirrer, and adjust the stirring speed until a vortex is generated that is approximately one-fifth the height of the water column. Mark the depth of the vortex.

[0132] Secure the 35mm slide mount to the alligator clamp of the 35mm slide mount holder so that the long end of the slide mount is parallel to the water surface. The depth adjuster of the holder should be set so that when dropped, the end of the clip is 0.6 cm below the water surface. One of the short sides of the slide mount should be next to the side of the beaker and the other should be positioned directly above the center of the stirring rod so that the film surface is perpendicular to the flow of water.

[0133] In a single action, the fixed slide and clip are dropped into the water, and the timer is started. Disintegration occurs when the film breaks. Once all visible film has been released from the slide mount, the slide is raised out of the water while continuing to monitor the solution for any undissolved film fragments. When dissolution occurs, all film fragments are no longer visible, and the solution becomes clear.

[0134] The results should include: complete identification of the sample, individual and average decay and dissolution times, and the water temperature at which the sample was tested.

[0135] The film disintegration time (I) and film dissolution time (S) can be corrected for the standard or reference film thickness using the exponential algorithms shown below in Equations 1 and 2, respectively. I 補正 =I 実測 × (Reference thickness / Actual thickness) 1.93 [1] S 補正 =S 実測 × (Reference thickness / Actual thickness) 1.83 [2]

[0136] The films were also tested for disintegration and dissolution in saltwater. For these experiments, the MSTM-205 method was performed as described above, except that the films were immersed in a 500 mL solution of 3.5% sodium chloride in 5°C distilled water instead of 500 mL of distilled water at 5°C. Disintegration and dissolution times in saltwater were determined using the same criteria used to determine disintegration and dissolution times in water.

[0137] DSC method (MSTM 122) To avoid weight loss during temperature rise, the tests were performed using a TA Instruments Q2000 differential scanning calorimeter (DSC), or an equivalent equipped with a 50 mL / min nitrogen purge and a TZERO aluminum sealed pan (available from TA Instruments). The film specimen to be tested was cut into small pieces to provide a whole sample of approximately 3–5 mg (e.g., approximately three stacked cut film pieces) that fits into the pan. The DSC test is performed by equilibrating the sample at -80°C, then (1) heating the sample to 75°C at a rate of 10°C / min to start generating the first DSC heating curve, (2) maintaining the sample at 75°C for 10 minutes, (3) heating the sample from 75°C to 200°C at a rate of 10°C / min to complete the first DSC heating curve, (4) cooling the sample to -75°C at a rate of -5°C / min to generate the DSC cooling curve, and optionally (5) reheating the sample to 200°C at a rate of 10°C / min to generate the second DSC heating curve. Once the curves are generated, transitions due to glass transition, melting, and crystallization are assigned, the glass transition temperature, melting temperature, and crystallization temperature (Tg, Tm, and Tc, respectively) are determined from the first DSC heating curve, and the melting or crystallization enthalpy is determined according to standard calorimetry.

[0138] Optionally, the second glass transition of the sample and the corresponding second glass transition temperature (Tg2) can be determined from the second DSC heating curve generated during the reheating step (5). The heating step (3) of the method for measuring Tg removes substantially all water from the film sample; therefore, Tg2 is the “dry” glass transition temperature corresponding to the glass transition of the film after the removal of residual water (i.e., during the first heating step).

[0139] Glass transitions can be identified from DSC data by methods known to those skilled in the art, such as ASTM E1356 or equivalents. Generally, glass transitions can be identified from DSC data as step changes in the DSC heating curve during the heating step (3) (related to Tg) and, optionally, during the reheating step (5) (related to Tg2).

[0140] Tensile strength test Films characterized by or tested for tensile strength according to tensile strength (TS) testing are analyzed as follows: The procedure involves determining tensile strength in accordance with ASTM D 882 ("Standard Test Method for Tensile Properties of Thin Plastic Sheeting") or its equivalent. An INSTRON tensile testing apparatus (Model 5544 tensile tester or equivalent) is used to collect film data. At least three test specimens, each cut with a reliable cutting tool to ensure dimensional stability and repeatability, are tested longitudinally (MD) (if applicable) for each measurement. The films to be tested are conditioned for at least 24 hours in an environment of 23±2.0°C and 35±5% relative humidity, and the tensile strength test is also performed in an environment of 23±2.0°C and 35±5% relative humidity. For tensile strength, a 1-inch (2.54 cm) wide sample of a single film sheet with a thickness of 76 μm is prepared. Next, the sample is transferred to an INSTRON tensile testing machine, and the test is carried out while minimizing exposure to a 35% relative humidity environment. The tensile testing machine, equipped with a 500N load cell, is prepared and calibrated according to the manufacturer's instructions. The correct grips and faces are installed (INSTRON grips with rubber-coated, 25mm wide, model number 2702-032 faces, or equivalent). The sample is mounted on the tensile testing machine and analyzed to determine the tensile strength (i.e., the stress required to break the film).

[0141] Young's modulus was determined as the gradient of the linear fit of stress-strain data over a strain range of 1–3%.

[0142] Elongation at break test The procedure includes determining elongation at break based on ASTM D882 ("Standard Test Method for Tensile Properties of Thin Plastic Sheeting") or an equivalent. An INSTRON® tensile testing apparatus (Model 5544 tensile tester or equivalent) is used to collect film data. At least three test specimens, each cut with a reliable cutting tool to ensure dimensional stability and repeatability, are tested longitudinally (MD) (if applicable) for each measurement. The film to be tested is conditioned for at least 24 hours in an environment of 23±2.0°C and 35±5% relative humidity, and the elongation at break test is also performed in an environment of 23±2.0°C and 35±5% relative humidity. For determining elongation at break, a 1-inch (2.54 cm) wide sample of a single film sheet with a thickness of 1.4±0.15 mil (approximately 35.6±3.8 μm) is prepared. Next, the sample is transferred to an INSTRON® tensile testing machine, and the test is carried out while minimizing exposure to a 35% relative humidity environment. The tensile testing machine, equipped with a 500N load cell, is prepared and calibrated according to the manufacturer's instructions. The correct grips and faces are attached (INSTRON® grips with rubber-coated, 25mm wide, model number 2702-032 faces, or equivalent). The sample is mounted on the tensile testing machine and analyzed to determine the strain at fracture (i.e., Young's modulus is applied).

[0143] resistance The resistance of the water-soluble film was measured using a digital multimeter, by clipping the multimeter leads to the film sample with the leads positioned 1 inch apart. The measurement was repeated three times. To ensure consistency, multiple resistance values ​​were obtained with the leads clipped at different positions on the sample. Generally, resistance was measured after the sample had been prepared to be measured under fixed temperature and humidity conditions as described herein. In particular, as used herein and unless otherwise specified, the resistance of a “dry” sample refers to the resistance of a sample measured immediately after the sample has been prepared for at least 24 hours in a 23°C / 35%RH environment.

[0144] Unless otherwise specified, the films evaluated for resistance contained a salt in an equimolar amount with 10 PHR of calcium chloride. [Examples]

[0145] As described below, water-soluble films were prepared via solution casting. The films were tested for thermal properties (Tg, Tm, Tc, enthalpy of fusion, and enthalpy of crystallization) and mechanical properties (tensile strength, Young's modulus, % strain at break, collapse, and dissolution time) according to the test methods described herein.

[0146] Example 1 Films containing the amounts of PVOH homopolymer, plasticizers (i.e., polyols and sugar alcohols), additives, and optionally calcium chloride, as shown in Table 1, were prepared via solution casting. Amounts are indicated in PHR. In the films of Examples 1b and 1c, 10 PHR of different components of the plasticizer blend in the film of Example 1a were replaced with 10 PHR of calcium chloride. [Table 2]

[0147] Replacing sugar alcohol plasticizers or polyol plasticizers with calcium chloride affected the physical and thermal properties of the resulting films. Figures 1 to 3 show the DSC traces for Examples 1a to 1c, respectively. The heating, cooling, and reheating traces, generally described as steps (1), (2), and (3) respectively in the section on the DSC test method above, are labeled in Figures 1 to 3 according to (1), (2), and (3). The DSC trace for Example 1a shows peaks due to melting and crystallization, while the DSC traces for Examples 1b and 1c do not show such transitions. As shown in Table 1, replacing sugar alcohol plasticizers with calcium chloride resulted in an increase in the glass transition temperature. Examples 1b and 1c also exhibited significantly faster decay and dissolution compared to films without calcium chloride.

[0148] While not intended to be constrained by theory, it is believed that calcium chloride disrupted the crystallinity of the PVOH resins, including those in Examples 1b and 1c, to such an extent that separate transitions associated with crystallization during melting and cooling could not be observed by DSC. Furthermore, it is believed that calcium chloride did not substantially plasticize the films, as evidenced by the increased glass transition temperature compared to films without calcium chloride.

[0149] Therefore, Example 1 demonstrates a film of the present disclosure having improved thermal properties and faster solubility compared to a film that does not contain metal salts.

[0150] Example 2 Films containing the amounts of PVOH homopolymer, plasticizer, additives, and calcium chloride shown in Table 2, with an increased amount of calcium chloride, were prepared via solution casting. The amounts are indicated in PHR. [Table 3]

[0151] Table 2 shows that the addition of calcium chloride had a clear effect on several mechanical properties. Tensile strength was minimally affected only by the addition of up to approximately 16 PHR of calcium chloride, while Young's modulus consistently increased across the same range of calcium chloride content. Above 16 PHR of calcium chloride, both tensile strength and Young's modulus began to decrease. Strain at break was only slightly affected by the addition of calcium chloride. Adding 2 PHR reduced the strain at break by approximately 25% compared to films without calcium chloride, but increasing the calcium chloride content from 2 PHR to 24 PHR had little further effect on the strain at break, indicating that the film maintained high flexibility at all levels of added calcium chloride.

[0152] The addition of calcium chloride also had a clear effect on several thermal properties. Adding calcium chloride above 2 PHR increased the glass transition temperature (both Tg and Tg2), indicating that the addition of calcium chloride did not have a clear plasticizing effect on the film. However, adding up to 10 PHR of calcium chloride decreased the melting temperature of the film, and films containing more than 10 PHR of calcium chloride did not exhibit a melting or crystallization transition visible by DSC analysis, similar to the calcium chloride-containing film in Example 1.

[0153] Therefore, Example 2 shows a film of the present disclosure that exhibits improved thermal properties with increasing metal salt concentration while maintaining excellent strength and flexibility.

[0154] Example 3 Films containing the amounts of PVOH homopolymer, plasticizer, additives, and various salts shown in Table 3 were prepared by solution casting. For ease of comparison, the data for Example 2a, a film without added salts, and Example 2e, a film containing 10 PHR of calcium chloride are included in the table. Examples 3a-3d contained magnesium chloride, calcium acetate (Ca(OAc)2), manganese acetate (Mn(OAc)2), and sodium chloride in amounts equal to 10 PHR of calcium chloride in Example 2e, respectively. The amounts are indicated in PHR. Because the salts have different molar masses, the equimolar amounts of each salt have different weights, as shown in the table by the different PHR levels of the salts in each film. [Table 4]

[0155] The addition of different salts had varying effects on the thermal properties of the resulting films. The magnesium chloride-containing film of Example 3a did not exhibit distinct transitions associated with melting or crystallization, making it impossible to determine the melting and crystallization enthalpies. This is similar to the behavior of the calcium chloride-containing film of Example 2e, where no crystallization transition was detected, only a weak melting transition. In this respect, calcium and magnesium chlorides had a more pronounced effect on the melting and crystallization of the films than divalent acetate salts (Examples 3b and 3c) and monovalent chloride salts (Example 3d).

[0156] The addition of each salt increased the film Tg compared to films without the added salt. The increase in Tg was most pronounced for magnesium and manganese salts. Considering the increase in Tg, none of the added salts effectively helped to plasticize the PVOH film.

[0157] With a few exceptions, the mechanical properties of the films were generally less sensitive to the addition of salt or the selection of added salts than to their thermal properties. Each salt-containing film exhibited a fracture strain approximately 30–45% lower than the film without added salt (2a), indicating that the addition of salt reduced the elasticity of the film, although there was no clear difference in the % fracture strain between the salt-containing films. The tensile strength of all but one of the salt-containing films was higher than that of the salt-free films, and the tensile stress was not as sensitive to the selection of added salts, with the exception of the calcium chloride-containing film, which had a tensile strength slightly lower than that of the salt-free film. All salt-containing films also exhibited a higher Young's modulus than the salt-free films, showing a more pronounced dependence on the selection of salts; the calcium acetate-containing film showed an almost 10-fold increase compared to the salt-free film, and the other salt-containing films showed an increase of approximately 2–4 times.

[0158] Films containing divalent chloride salts, Examples 2e and 3a, also exhibited faster decay and dissolution than films without salts. Other salts had minimal effect on decay and dissolution time.

[0159] Therefore, Example 3 demonstrates a metal salt-containing film according to the present disclosure that exhibits superior mechanical properties and improved thermal properties compared to a film without added metal salts. Example 3 also demonstrates that the addition of divalent metal halide salts has a significant effect on the thermal properties and solubility of the film.

[0160] Example 4 Films containing the amounts of PVOH homopolymer, additives, and calcium chloride shown in Table 4 were prepared via solution casting. The films did not contain polyols or sugar alcohol plasticizers. Amounts are indicated in PHR. [Table 5]

[0161] In general, the films of Example 4 exhibited high tensile strength, high Young's modulus, and low strain at break, consistent with the absence of plasticizers in these films. Increasing the amount of calcium chloride in the plasticizer-free films from 0 PHR to approximately 16 PHR had only a slight effect on tensile stress and strain at break. Films without calcium chloride did not disintegrate or dissolve over the time frame of the test method, but the films became more easily water-soluble with increasing calcium chloride content, as indicated by the decrease in dissolution and disintegration time up to 24 PHR of calcium chloride filling.

[0162] With 24 PHR of calcium chloride filling, there were gradual changes in several film properties. Tensile strength decreased by approximately 30-40% compared to films containing 2-16 PHR of calcium chloride, and films containing 24 PHR of calcium chloride were far less brittle than films containing 2-16 PHR of calcium chloride, as evidenced by the increase in fracture strain from less than 10% to over 200%.

[0163] In all of the films in Example 4, no glass transition was observed during the initial DSC heating pass, but a glass transition was observed in each film during the second DSC heating pass. Upon reheating, the films exhibited a transition within the DSC, which was due to the glass transition in film samples that contained little to no water.

[0164] Films containing 4 PHR or more of calcium chloride did not exhibit crystallization transitions due to DSC, and did not exhibit transitions due to crystallization, which was consistent with the results of other calcium chloride-containing films such as Examples 2d-2g.

[0165] While not intended to be constrained by theory, it is believed that increasing the calcium chloride content of a film increases its residual water content, resulting in a film that is more easily water-degradable and water-soluble.

[0166] Therefore, Example 4 demonstrates that the effects of metal salts on the thermal and mechanical properties of a film can also be achieved with films that do not contain plasticizers.

[0167] Example 5 Films containing the amounts of PVOH homopolymer, additives, calcium chloride, and varying amounts of polyols and sugar alcohols as plasticizers shown in Table 5 were prepared by solution casting. Amounts are indicated in PHR. The total plasticizer content of each film (i.e., glycerin + xylitol) is listed in the table in parentheses for clarity and does not indicate additional plasticizers within each film. The weight ratio of polyols to sugar alcohols (P / S) in each film is also listed. [Table 6]

[0168] In general, Examples 5a–5f demonstrate that the addition of 10 PHR of calcium chloride did not disrupt the expected trends in thermal and mechanical properties across a range of plasticizer levels and ratios. In particular, as shown in Examples 5a, 5b, 5d, and 5e, with increasing plasticizer content, Tg and Tg2 generally decreased, tensile strength and Young's modulus decreased, % strain at break increased, and collapse and dissolution times decreased. The presence of calcium chloride in the film did not interfere with these expected trends. Furthermore, all films had very low or undetectable melting and crystallization enthalpies, consistent with the results of other films containing 10 PHR of calcium chloride as described above. Therefore, the presence of calcium chloride in the film can provide the benefit of reducing the energy barrier to melting without substantially interfering with the expected effects of the plasticizer added to the film.

[0169] Therefore, Example 5 demonstrates that the effects of calcium chloride on the thermal and mechanical properties of a film can be achieved across a range of plasticizer levels and compositions.

[0170] Example 6 Films containing various PVOH resins, plasticizers, additives, and calcium chloride in the amounts shown in Table 6 were prepared by solution casting. The amounts are indicated in PHR. Table 6 includes the type, viscosity, and degree of hydrolysis of each PVOH resin. With respect to Examples 6g to 6i, which include acrylate-modified PVOH, the resins are further characterized by their degree of ring opening (RO). For example, PVOH copolymer resins having pendant carboxyl groups, such as polyvinyl alcohol acrylate polymers, can form lactone rings through the reaction of adjacent pendant carboxyl groups and alcohol groups. With respect to Examples 6g to 6i, "0%RO" or "70%RO" indicates that 0% or approximately 70% of the lactone rings on the resin backbone are open to form the corresponding pendant carboxyl groups and alcohol groups, respectively. [Table 7]

[0171] Generally, films containing 10 PHR of calcium chloride had a lower enthalpy of melting than the film of Example 2a, which did not contain calcium chloride. This effect was observed for films containing various types and molecular weights of PVOH resin. The reduction in enthalpy of melting effect was less pronounced in Example 6d, which contained a PVOH homopolymer with 100% DH (i.e., a homopolymer with 100% acetate groups in poly(vinyl acetate) converted to hydroxyl groups), and the melting temperature of this film was 10°C higher than that of Example 2a. Example 6d also had very long decay and dissolution times, consistent with the expected low solubility of PVOH with 100% DH resin; the addition of calcium chloride had virtually no effect on the solubility of this film. For PVOH homopolymers and maleate-modified PVOH copolymers, the expected dependence of other film properties, including tensile strength, Young's modulus, % strain at break, and decay and dissolution times, on the PVOH molecular weight was not affected by the addition of calcium chloride.

[0172] Adding calcium chloride to a film containing 0% ring-opened acrylate-modified PVOH copolymer had a similar effect on thermal properties as observed when adding calcium chloride to a film containing PVOH homopolymer or maleate-modified PVOH copolymer. Comparing Examples 6g and 6h, the addition of 10 PHR of calcium chloride resulted in a reduction of melting temperature and enthalpy of melting, as well as the suppression of any measurable crystallization transition. The effect of adding calcium chloride was even more pronounced in Example 6i, which contained a partially ring-opened acrylate-modified PVOH copolymer, where melting and crystallization transitions were suppressed, and the film was far more easily water-soluble than an otherwise identical film containing an un-ring-opened acrylate-modified PVOH copolymer.

[0173] Therefore, Example 6 demonstrates that the effect of adding a metal salt was achieved with respect to films containing PVOH homopolymers and films containing maleate-modified or acrylate-modified PVOH copolymers.

[0174] Example 7 Films containing the amounts of PVOH homopolymer, plasticizer, additives, and sodium or lithium chloride shown in Table 7 were prepared by solution casting. The amounts are indicated in PHR. The amount of each salt is approximately equimolar to 10 PHR of calcium chloride (7a, 7c) and 20 PHR of calcium chloride (7b, 7d). [Table 8]

[0175] In general, the addition of lithium chloride had a more significant effect on film melting and crystallization than the addition of sodium chloride. While the addition of sodium chloride reduced the enthalpy of melting compared to the film without salt, in Example 2a, the addition of lithium chloride provided a greater reduction in enthalpy of melting and a significant reduction in enthalpy of crystallization. Furthermore, the addition of 7.7 PHR of lithium chloride was sufficient to suppress separate melting and crystallization transitions. Thus, the addition of lithium chloride provided a similar effect on the thermal properties of the film as the addition of calcium chloride. Regarding mechanical properties, the addition of lithium chloride had less significant an effect on % strain at break than the addition of sodium chloride; that is, films containing sodium chloride or lithium chloride showed a reduction in % strain at break compared to the film in Example 2a, but the reduction was smaller in the case of lithium chloride. Furthermore, increasing the amount of salt for both sodium chloride and lithium chloride (i.e., Examples 7b vs. 7a, and Examples 7d vs. 7c) provided more flexible films, as indicated by increases of 25% and 17% in % strain at break, respectively.

[0176] Therefore, Example 7 demonstrates that the addition of monovalent salts affects the thermal and mechanical properties of the film, and that the addition of lithium chloride generally has a more significant effect on the film's properties than the addition of sodium chloride.

[0177] Example 8: Saltwater solubility Films containing the amounts of PVOH homopolymer, plasticizer, additives, and calcium chloride shown in Table 8, or films without calcium chloride, were prepared by solution casting. The amounts are indicated in PHR. Table 8 includes the disintegration time and dissolution time of each film in brine (3.5% sodium chloride solution) as determined according to the modified MSTM205 method described above. [Table 9]

[0178] As shown in Table 8, films containing calcium chloride exhibited saline solubility up to approximately 50% faster than films without calcium chloride. While the films generally dissolved more slowly in saline water than in water (as can be seen, for example, by comparing the dissolution times in saline water and in water for films with the same composition, i.e., Examples 8a and 2a, and Examples 8c and 2f), the relative increase in solubility upon the addition of calcium chloride was greater for saline water solubility compared to solubility in water.

[0179] Example 9: Increased conductivity Films containing a completely hydrolyzed PVOH homopolymer (100% DH, 30 cP) and an equimolar amount of a metal salt with 10 phr of calcium chloride were prepared by solution casting. The films were measured in their dry state (1) after being treated at 50°C for 48 hours, and in their hydrated state (2) after the dried films treated according to step (1) were immersed in distilled water for 5 minutes, dried to remove bulk water, and treated at 23°C and 50% RH for 3 hours. The resistances of the films containing the PVOH homopolymer and calcium acetate (Ca(OAc)2), magnesium chloride, or sodium chloride, as well as the ratio of resistance in the dry state to resistance in the hydrated state for each film, are shown in Table 9. [Table 10]

[0180] Films containing metal salts underwent a substantial decrease in resistance, ranging from three to five orders of magnitude, upon conversion from a dry to a hydrated state. While not intended to be constrained by theory, it is thought that ions in the metal salt-containing film facilitate charge transfer through the hydrated film, and the dry film contains enough water for the ions in the film to conduct charge, effectively making the dry film non-conductive.

[0181] Example 10: Conductivity By solution casting, films containing PVOH homopolymer (88% DH, 13 cP) and salts in equimolar amounts with 10 PHR of calcium chloride, as well as films containing the same PVOH homopolymer but without the salts, were prepared. Films where two salts are listed contain equimolar amounts of each salt. The resistance of each film was measured after the film was first dried, i.e., adjusted at 23°C / 35% RH for at least 24 hours. The films were then moved to a 23°C / 50% RH environment or a 38°C / 80% RH environment, and the resistance was measured after 30 minutes, 60 minutes, 120 minutes, and 24 hours in each environment. The results are shown in Table 10, and the measured resistance values ​​are shown in megaohms (MΩ). ">" indicates that the resistance is too high to be measured with a digital multimeter, i.e., above approximately 62 MΩ. [Table 11]

[0182] Table 10 shows that for films and conditions under which resistance was measurable, resistance decreased during adjustment in 50% and 80% RH environments, and that resistance was generally lower when stored at 80% RH compared to storage at 50% RH. In most cases, films with added salt exhibited lower resistance compared to films without added salt, following adjustment under the same time, temperature, and humidity conditions. Generally, the addition of chloride salts had a greater effect in reducing resistance compared to the addition of salts of other anions. The addition of ammonium chloride, in particular, resulted in a reduction in resistance (i.e., higher conductivity) compared to the addition of the same molar amount of other salts.

[0183] Example 11 Films containing the amounts of PVOH homopolymer (88% DH, 13 cP), plasticizers, additives, and zinc salts (zinc chloride or zinc acetate, respectively; Examples 11a and 11b), or films without salt addition (Example 2a), as shown in Table 11, were prepared by solution casting. Amounts are indicated in PHR. Disintegration and dissolution times were measured in water at 10°C. For ease of comparison, data for Example 2a, a film without added salts, are included in the table. [Table 12]

[0184] In general, the addition of zinc chloride or zinc acetate had less significant an effect on the thermal properties of the film compared to the addition of other polyvalent salts. For example, the addition of zinc salts had less significant an effect on Tg and Tg2 compared to the addition of calcium, magnesium, or manganese salts. When 5.0 PHR of zinc chloride or 10.0 PHR of zinc acetate was added to the film of Example 2a, Tg increased by 7°C and Tg2 increased by up to 14°C. However, when 10.0 PHR of calcium chloride was added to the film of Example 2a (Example 2e), Tg and Tg2 increased by 18°C ​​and 35°C, respectively. The addition of equimolar amounts of magnesium chloride or manganese acetate to 10.0 PHR of calcium chloride (Examples 3a and 3c, respectively) resulted in greater increases in Tg (35°C, 42°C) and Tg2 (45°C, 18°C) than those obtained from the addition of 10.0 PHR of zinc acetate. The addition of zinc salts also had a minimal effect on reducing the melting temperature. The addition of 10.0 PHR of zinc acetate resulted in a 5°C reduction in melting temperature compared to the film of Example 2a, while the film of Example 2e (10.0 PHR of calcium chloride) showed a 21°C reduction in melting temperature. The addition of an amount of magnesium chloride equal to that of 10.0 PHR of calcium chloride (Example 3a) completely suppressed the melting transition.

[0185] Example 12 Films containing the amounts of PVOH homopolymer (88% DH, 13 cP), plasticizer, additives, and magnesium chloride shown in Table 12 were prepared by solution casting. The amounts are indicated in PHR. Disintegration and dissolution times were measured in water at 10°C. For ease of comparison, data for Example 2a, a film without added salts, is included in the table. [Table 13]

[0186] The addition of magnesium chloride significantly affected the thermal properties of the film compared to films without added metal salts. Adding 3 PHR of magnesium chloride reduced the film's melting temperature by 16°C, nearly eliminated the enthalpy of fusion transition, and the film containing 3 PHR of magnesium chloride showed no measurable crystallization transition. Adding 6 PHR or 9 PHR of magnesium chloride suppressed any melting transition. Adding 3 PHR of magnesium chloride accelerated dissolution compared to films without added metal salts, and further addition of magnesium chloride slightly reduced the disintegration or dissolution time.

[0187] In general, the addition of magnesium chloride has a greater effect on thermal properties compared to the addition of calcium chloride. For example, the addition of 3 PHR of magnesium chloride had a similar effect on melting and crystallization properties compared to the addition of 8 PHR of calcium chloride (Example 2d), including a similar reduction in Tm, a substantial reduction in enthalpy of melting, and suppression of a measurable crystallization transition, which was not observed with the addition of smaller amounts (2 PHR, 4 PHR) of calcium chloride.

[0188] Since various modifications and changes to accommodate specific operating requirements and environments will be obvious to those skilled in the art, this disclosure should not be considered limited to the embodiments selected for illustrative purposes, but rather encompasses all changes and modifications that do not constitute a departure from the true spirit and scope of this disclosure.

[0189] Therefore, the above statements are provided solely for the purpose of clarifying understanding, and modifications within the scope of this disclosure may be obvious to those skilled in the art, so no unnecessary limitations should be inferred therefrom.

[0190] Throughout this specification, where compounds, compositions, articles, methods, and processes are described as comprising components, steps, or materials, it is considered that the compositions, processes, or apparatus may also comprise, essentially consist of, or consist of any combination of the listed components or materials, unless otherwise described.

Claims

1. It is a water-soluble film, The water-soluble film comprises a mixture of polyvinyl alcohol (PVOH) resin, a plasticizer, and a polyvalent metal salt, wherein the polyvalent metal salt is present in the water-soluble film in an amount sufficient to reduce the enthalpy of melting of the film by at least 20% compared to the enthalpy of melting of a film otherwise identical without the polyvalent metal salt. The PVOH resin is present in the film in an amount of at least 50% by weight, based on the total weight of the film. A water-soluble film in which the polyvalent metal salt contains an inorganic anion.

2. The water-soluble film according to claim 1, wherein the polyvalent metal salt is selected from calcium salts, magnesium salts, manganese salts, barium salts, iron salts, and mixtures thereof.

3. The water-soluble film according to claim 1 or 2, wherein the inorganic anion is selected from halide, nitrate, sulfate, phosphate, and combinations thereof.

4. The water-soluble film according to any one of the prior claims, wherein the film comprises calcium chloride.

5. The water-soluble film according to any one of claims 1 to 3, wherein the film comprises magnesium chloride.

6. The film is a water-soluble film according to any one of the prior claims, wherein the film does not contain a zinc salt.

7. The water-soluble film according to any one of the prior claims, wherein the polyvalent metal salt is present in the water-soluble film in an amount ranging from about 1 part to about 30 parts per 100 parts of PVOH resin (PHR).

8. The water-soluble film according to claim 7, wherein the polyvalent metal salt is present in the water-soluble film in an amount ranging from about 3 parts to about 20 parts per 100 parts of PVOH resin (PHR).

9. The water-soluble film according to any one of the prior claims, wherein the plasticizer is selected from the group consisting of polyols, sugar alcohols, polyethers, amines, and mixtures thereof.

10. The water-soluble film according to claim 9, wherein the plasticizer is selected from glycerol, diglycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol up to 400 MW, neopentyl glycol, 1,2-propylene glycol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, trimethylolpropane, polyether polyol, isomalt, maltitol, sorbitol, xylitol, erythritol, adonitol, dalcitol, pentaerythritol, mannitol, ethanolamine, and mixtures thereof.

11. The water-soluble film according to any one of the prior claims, wherein the plasticizer does not contain a divalent metal.

12. The water-soluble film according to any one of the prior claims, wherein the plasticizer is present in the water-soluble film in an amount ranging from about 10 parts to about 50 parts per 100 parts of PVOH resin (PHR).

13. The water-soluble film according to any one of the prior claims, wherein the PVOH resin comprises one or more PVOH homopolymers, one or more PVOH copolymers, or a mixture thereof.

14. The water-soluble film according to claim 13, wherein the PVOH resin comprises a PVOH homopolymer.

15. The water-soluble film according to claim 14, wherein the PVOH resin comprises a blend of two or more PVOH homopolymers.

16. The water-soluble film according to claim 13, wherein the PVOH resin comprises an anionic modified PVOH copolymer.

17. The water-soluble film according to claim 16, wherein the PVOH resin comprises a blend of two or more anionically modified PVOH copolymers.

18. The water-soluble film according to claim 10, wherein the PVOH resin comprises a blend of a PVOH homopolymer and an anionically modified PVOH copolymer.

19. The water-soluble film according to any one of the prior claims, wherein the film comprises one or more additives selected from fillers, surfactants, antiblocking agents, antioxidants, defoaming agents, bleaching agents, aversive agents, irritants, other functional components, and combinations thereof.

20. The water-soluble film according to any one of the prior claims, characterized in that the film has a crystallization enthalpy of less than approximately 30 J / g, less than approximately 20 J / g, less than approximately 15 J / g, less than approximately 10 J / g, or less than approximately 1 J / g when determined by DSC.

21. When the aforementioned film is measured according to a tensile strength test, it exhibits a strength of approximately 20 to 200 N / mm². 2 , or approximately 25 to approximately 100 N / mm 2 , or approximately 30 to approximately 50 N / mm 2 A water-soluble film according to any one of the prior claims, characterized by having a tensile strength within a certain range.

22. The water-soluble film according to any one of the prior claims, characterized in that the film has a strain at break that, when measured according to a break elongation test, is in the range of approximately 250% to approximately 500%, approximately 300% to approximately 450%, or approximately 350% to approximately 400%.

23. When the aforementioned film is measured according to a tensile strength test, it exhibits a strength of approximately 40 to 1000 N / mm². 2 , or approximately 50 to 500 N / mm 2 , or approximately 60 to 300 N / mm 2 , or approximately 100 to approximately 200 N / mm 2 A water-soluble film according to any one of the prior claims, characterized by having a Young's modulus within the range.

24. The water-soluble film according to any one of the prior claims, provided that the film is provided with a thickness of about 76 microns, and has a disintegration time of less than 60 seconds and a dissolution time of less than 90 seconds at 5°C when measured according to the MonoSol Test Method MSTM 205.

25. If the film is provided with a thickness of about 76 microns, the water-soluble film according to any one of the prior claims has a decay time of at least 30%, at least 40%, at least 45%, or at least 50% of the decay time of a film otherwise identical that does not contain the polyvalent salt, wherein the decay time is measured in an aqueous solution of 3.5% by weight of sodium chloride at 5°C according to the MonoSol Test Method MSTM 205.

26. A water-soluble film according to any one of the prior claims, wherein, when the film is provided with a thickness of about 76 microns, it has a dissolution time of at least 30%, at least 40%, at least 45%, or at least 50% of the dissolution time of a film otherwise identical that does not contain the polyvalent salt, and the dissolution time is measured in an aqueous solution of 3.5% by weight of sodium chloride at 5°C according to the MonoSol Test Method MSTM 205.

27. A water-soluble film according to any one of the prior claims, wherein the film is characterized by a crystallization temperature of at least 5°C, at least 10°C, at least 20°C, at least 30°C, or at least 40°C, which is the same as the film in other respects and does not contain the polyvalent metal salt.

28. The water-soluble film according to any one of the prior claims, wherein the film is characterized by having a glass transition temperature that is at least 10°C higher, at least 15°C higher, or at least 20°C higher than the glass transition temperature of a film that is otherwise identical and does not contain the polyvalent metal salt.

29. A water-soluble film according to any one of the prior claims, further comprising a polyvalent metal salt having an organic anion.

30. The water-soluble film according to any one of the prior claims, wherein the organic anion comprises acetate, citrate, gluconate, lactate, or a mixture thereof.

31. A water-soluble film according to any one of the prior claims, further comprising a monovalent metal salt.

32. The water-soluble film according to claim 31, wherein the monovalent metal salt is selected from sodium salts and lithium salts.

33. A water-soluble film comprising a mixture of polyvinyl alcohol (PVOH) resin, a plasticizer, and a lithium salt.

34. The lithium salt is present in the water-soluble film in an amount sufficient to reduce the enthalpy of melting of the film by at least 20% compared to the enthalpy of melting of a film otherwise identical without the lithium salt. The PVOH resin is present in the film in an amount of at least 50% by weight, based on the total weight of the film. The water-soluble film according to claim 33, wherein the lithium salt contains an inorganic anion.

35. The water-soluble film according to claim 33 or 34, wherein the lithium salt is present in the water-soluble film in an amount ranging from about 1 part to about 30 parts per 100 parts of PVOH resin (PHR).

36. The water-soluble film according to any one of claims 33 to 35, wherein the plasticizer is selected from the group consisting of polyols, sugar alcohols, polyethers, amines, and mixtures thereof.

37. The water-soluble film according to claim 36, wherein the plasticizer is selected from glycerol, diglycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol up to 400 MW, neopentyl glycol, 1,2-propylene glycol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, trimethylolpropane, polyether polyol, isomalt, maltitol, sorbitol, xylitol, erythritol, adonitol, dalcitol, pentaerythritol, mannitol, and mixtures thereof.

38. The water-soluble film according to any one of claims 33 to 37, wherein the plasticizer does not contain divalent metals.

39. The water-soluble film according to any one of claims 33 to 38, wherein the plasticizer is present in the water-soluble film in an amount ranging from about 10 parts to about 50 parts per 100 parts of PVOH resin (PHR).

40. The water-soluble film according to any one of claims 33 to 39, wherein the PVOH resin comprises one or more PVOH homopolymers, one or more PVOH copolymers, or a mixture thereof.

41. The water-soluble film according to claim 40, wherein the PVOH resin comprises a PVOH homopolymer.

42. The water-soluble film according to claim 40 or 41, wherein the PVOH resin comprises an anionic modified PVOH copolymer.

43. The water-soluble film according to any one of claims 33 to 42, wherein the film comprises one or more additives selected from fillers, surfactants, antiblocking agents, antioxidants, defoaming agents, bleaching agents, aversive agents, irritants, other functional components, and combinations thereof.

44. The water-soluble film according to any one of claims 33 to 43, wherein the film is characterized by having a glass transition temperature that is at least 5°C higher, at least 10°C higher, at least 15°C higher, or at least 20°C higher than the glass transition temperature of a film that is otherwise identical and does not contain the lithium salt.

45. The water-soluble film according to any one of claims 33 to 44, characterized in that the film has a fracture strain in the range of approximately 250% to approximately 700%, or approximately 300% to approximately 600%, or approximately 400% to approximately 500%, as determined by a tensile strength and elastic modulus test.

46. The water-soluble film according to any one of claims 33 to 45, wherein, when the film is provided with a thickness of about 76 microns, it has a disintegration time of less than 60 seconds when measured according to the MonoSol Test Method MSTM 205.

47. The water-soluble film according to any one of claims 33 to 46, wherein the film is provided with a thickness of about 76 microns and has a dissolution time of less than 90 seconds at 5°C when measured according to the MonoSol Test Method MSTM 205.

48. The water-soluble film according to any one of the prior claims, wherein the film further comprises ammonium chloride.

49. It is a water-soluble film, A water-soluble film comprising a mixture of polyvinyl alcohol (PVOH) resin, a plasticizer, and a salt, wherein the film has a dry resistance of less than approximately 60 MΩ (megaohms), less than approximately 50 MΩ, less than approximately 40 MΩ, or less than approximately 30 MΩ when measured according to a resistance test method.

50. The water-soluble film according to claim 49, wherein the salt is selected from the group consisting of guanidinium chloride, potassium chloride, ammonium chloride, and potassium iodide.

51. A water-soluble article comprising a water-soluble film according to any one of the prior claims, wherein the article is formed by thermoforming the water-soluble film at a temperature of 95°C or lower, or 90°C or lower, or 80°C or lower, or 70°C or lower, or 60°C or lower.

52. A water-soluble unit-dose article comprising at least one compartment and optionally a composition contained within the compartment, wherein the compartment comprises at least one wall, and at least one wall of the compartment comprises a water-soluble film according to any one of claims 1 to 47.

53. The water-soluble unit-dose article according to claim 52, wherein the composition contains citric acid.

54. The water-soluble unit-dose article according to claim 52, wherein the composition comprises a household care product or a personal care product.

55. A method for forming a water-soluble article, comprising thermoforming a water-soluble film according to any one of claims 1 to 47 at a temperature of 90°C or lower, 80°C or lower, 70°C or lower, 60°C or lower, 40°C or lower, or 25°C or lower.

56. It is a water-soluble fiber, The water-soluble fiber comprises a mixture of polyvinyl alcohol resin, a plasticizer, and a polyvalent metal salt, wherein the polyvalent metal salt is present in the water-soluble fiber in an amount sufficient to reduce the enthalpy of melting of the film by at least 20% compared to the enthalpy of melting of otherwise identical fibers that do not contain the polyvalent metal salt. The polyvinyl alcohol resin is present in the fibers in an amount of at least 50% by weight, based on the total weight of the film. The aforementioned polyvalent metal salt is a water-soluble fiber containing an inorganic anion.

57. A nonwoven web comprising a plurality of water-soluble fibers as described in claim 56.

58. A water-soluble unit-dose article comprising at least one compartment and optionally a composition contained within the compartment, wherein the compartment comprises at least one wall, and at least one wall of the compartment comprises the nonwoven web described in claim 57.

59. The water-soluble unit-dose article according to claim 58, wherein the composition contains citric acid.

60. The water-soluble unit-dose article according to claim 58, wherein the composition comprises a household care product or a personal care product.

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